From patchwork Mon Nov 25 12:08:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Christian_G=C3=B6ttsche?= X-Patchwork-Id: 13884867 Received: from server02.seltendoof.de (server02.seltendoof.de [168.119.48.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3468B2500BA for ; Mon, 25 Nov 2024 12:08:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.48.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732536518; cv=none; b=iDHHly5ivg2jQ2qqgXuGzbpBA2ZFL2J/1DqrAxrrEPLVQPf7ZLfGzPXmHYl6oEUaPRgXdy28Z9iS9D1zJ3bfsw0JQ+c/0ZFFkvs++zP5Jas8Q89FNZ/GcWrILz/VY7ThoxNxuFLruvAIYd/oZgMaKFH86Mw9ExLdRSMTeLqvafg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732536518; c=relaxed/simple; bh=FU9hOxAsf7+9rprPXtzqxlwq7WGorsjoDW/6yH6pfFQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=ctKO8FMYCPy889ZQw3u954Mn6uYwo8hQxHpEhr1ApWShvkgQESa8Ms5dNt9I8Zn8ULfBKYHhvpRVVYQcU0aBxRRaBe8N+y3fjgFt5yAKUYiA6Gry9n3Un0sPe4yZk+OV0zJcdJ+FsZJlYyg4jz88HShBuhoRFHICVOeA6vPpMu8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=seltendoof.de; spf=pass smtp.mailfrom=seltendoof.de; dkim=pass (2048-bit key) header.d=seltendoof.de header.i=@seltendoof.de header.b=D8/Gh7EO; arc=none smtp.client-ip=168.119.48.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=seltendoof.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=seltendoof.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=seltendoof.de header.i=@seltendoof.de header.b="D8/Gh7EO" From: =?utf-8?q?Christian_G=C3=B6ttsche?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=seltendoof.de; s=2023072701; t=1732536512; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=mtKidiXapmX3A9JU3r1UYAElvEUaIuKmxPRyI0z97GE=; b=D8/Gh7EOqElcUxFDB/8awkPv5eRgvMdqo6WY+t7CLhPOP0un5V6ZMROf0bLjY8KXhPnaFD XPSrjxuLqW+aR1fU0Kw/tK+XQLOXL/h06FyZ1yN6MuFYe35S/0P2jtttPeUZ3KbADu1u2H gJ51p0uryfzYIBAH1I2awlT9wcR/OYBdpwgQvg1wYQ2xnoPcdGFy5I5MHyT5r5aC0DyrRT tHunm/+oOn6IOGbpmun7cYDGmX471WvaqqHh0MvJY6ry+3VWBXN/qyjBuMno1upHSnKXTl Oe0OzgaqbNypn6NfcCpWvd2NFk29FupFB9SOG5tPcM1teLROQAUHIyvR1YOPqg== To: selinux@vger.kernel.org Cc: =?utf-8?q?Christian_G=C3=B6ttsche?= Subject: [PATCH v2 1/3] libselinux: avoid memory allocation in common file label lookup Date: Mon, 25 Nov 2024 13:08:25 +0100 Message-ID: <20241125120827.97332-1-cgoettsche@seltendoof.de> Reply-To: cgzones@googlemail.com Precedence: bulk X-Mailing-List: selinux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Christian Göttsche Remove a memory allocation during a common file label lookup, e.g. requested by restorecon(8)/setfiles(8), by using a local stack buffer for a potential lookup result. Additional minor optimization tweaks. Signed-off-by: Christian Göttsche --- v2: drop claim about this being the sole memory allocation, since applying a substitution path allocates as well --- libselinux/src/label_file.c | 103 +++++++++++++++++------------- libselinux/src/selinux_internal.h | 8 +++ 2 files changed, 68 insertions(+), 43 deletions(-) diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c index 189a5ed2..4e212aa4 100644 --- a/libselinux/src/label_file.c +++ b/libselinux/src/label_file.c @@ -1467,12 +1467,30 @@ FUZZ_EXTERN void free_lookup_result(struct lookup_result *result) } } -static struct lookup_result *lookup_check_node(struct spec_node *node, const char *key, uint8_t file_kind, bool partial, bool find_all) +/** + * lookup_check_node() - Try to find a file context definition in the given node or parents. + * @node: The deepest specification node to match against. Parent nodes are successively + * searched on no match or when finding all matches. + * @key: The absolute file path to look up. + * @file_kind: The kind of the file to look up (translated from file type into LABEL_FILE_KIND_*). + * @partial: Whether to partially match the given file path or completely. + * @find_all: Whether to find all file context definitions or just the most specific. + * @buf: A pre-allocated buffer for a potential result to avoid allocating it on the heap or + * NULL. Mututal exclusive with @find_all. + * + * Return: A pointer to a file context definition if a match was found. If @find_all was specified + * its a linked list of all results. If @buf was specified it is returned on a match found. + * NULL is returned in case of no match found. + */ +static struct lookup_result *lookup_check_node(struct spec_node *node, const char *key, uint8_t file_kind, + bool partial, bool find_all, struct lookup_result *buf) { struct lookup_result *result = NULL; struct lookup_result **next = &result; size_t key_len = strlen(key); + assert(!(find_all && buf != NULL)); + for (struct spec_node *n = node; n; n = n->parent) { uint32_t literal_idx = search_literal_spec(n->literal_specs, n->literal_specs_num, key, key_len, partial); @@ -1495,10 +1513,14 @@ static struct lookup_result *lookup_check_node(struct spec_node *node, const cha return NULL; } - r = malloc(sizeof(*r)); - if (!r) { - free_lookup_result(result); - return NULL; + if (likely(buf)) { + r = buf; + } else { + r = malloc(sizeof(*r)); + if (!r) { + free_lookup_result(result); + return NULL; + } } *r = (struct lookup_result) { @@ -1510,11 +1532,11 @@ static struct lookup_result *lookup_check_node(struct spec_node *node, const cha .next = NULL, }; + if (likely(!find_all)) + return r; + *next = r; next = &r->next; - - if (!find_all) - return result; } literal_idx++; @@ -1556,10 +1578,14 @@ static struct lookup_result *lookup_check_node(struct spec_node *node, const cha return NULL; } - r = malloc(sizeof(*r)); - if (!r) { - free_lookup_result(result); - return NULL; + if (likely(buf)) { + r = buf; + } else { + r = malloc(sizeof(*r)); + if (!r) { + free_lookup_result(result); + return NULL; + } } *r = (struct lookup_result) { @@ -1571,12 +1597,12 @@ static struct lookup_result *lookup_check_node(struct spec_node *node, const cha .next = NULL, }; + if (likely(!find_all)) + return r; + *next = r; next = &r->next; - if (!find_all) - return result; - continue; } @@ -1692,7 +1718,8 @@ FUZZ_EXTERN struct lookup_result *lookup_all(struct selabel_handle *rec, const char *key, int type, bool partial, - bool find_all) + bool find_all, + struct lookup_result *buf) { struct saved_data *data = (struct saved_data *)rec->data; struct lookup_result *result = NULL; @@ -1704,18 +1731,18 @@ FUZZ_EXTERN struct lookup_result *lookup_all(struct selabel_handle *rec, unsigned int sofar = 0; char *sub = NULL; - if (!key) { + if (unlikely(!key)) { errno = EINVAL; goto finish; } - if (!data->num_specs) { + if (unlikely(!data->num_specs)) { errno = ENOENT; goto finish; } /* Remove duplicate slashes */ - if ((next_slash = strstr(key, "//"))) { + if (unlikely(next_slash = strstr(key, "//"))) { clean_key = (char *) malloc(strlen(key) + 1); if (!clean_key) goto finish; @@ -1732,12 +1759,12 @@ FUZZ_EXTERN struct lookup_result *lookup_all(struct selabel_handle *rec, /* remove trailing slash */ len = strlen(key); - if (len == 0) { + if (unlikely(len == 0)) { errno = EINVAL; goto finish; } - if (len > 1 && key[len - 1] == '/') { + if (unlikely(len > 1 && key[len - 1] == '/')) { /* reuse clean_key from above if available */ if (!clean_key) { clean_key = (char *) malloc(len); @@ -1757,7 +1784,7 @@ FUZZ_EXTERN struct lookup_result *lookup_all(struct selabel_handle *rec, node = lookup_find_deepest_node(data->root, key); - result = lookup_check_node(node, key, file_kind, partial, find_all); + result = lookup_check_node(node, key, file_kind, partial, find_all, buf); finish: free(clean_key); @@ -1768,14 +1795,9 @@ finish: static struct lookup_result *lookup_common(struct selabel_handle *rec, const char *key, int type, - bool partial) { - struct lookup_result *result = lookup_all(rec, key, type, partial, false); - if (!result) - return NULL; - - free_lookup_result(result->next); - result->next = NULL; - return result; + bool partial, + struct lookup_result *buf) { + return lookup_all(rec, key, type, partial, false, buf); } /* @@ -1835,7 +1857,7 @@ static bool hash_all_partial_matches(struct selabel_handle *rec, const char *key { assert(digest); - struct lookup_result *matches = lookup_all(rec, key, 0, true, true); + struct lookup_result *matches = lookup_all(rec, key, 0, true, true, NULL); if (!matches) { return false; } @@ -1864,25 +1886,20 @@ static bool hash_all_partial_matches(struct selabel_handle *rec, const char *key static struct selabel_lookup_rec *lookup(struct selabel_handle *rec, const char *key, int type) { - struct lookup_result *result; - struct selabel_lookup_rec *lookup_result; + struct lookup_result buf, *result; - result = lookup_common(rec, key, type, false); + result = lookup_common(rec, key, type, false, &buf); if (!result) return NULL; - lookup_result = result->lr; - free_lookup_result(result); - return lookup_result; + return result->lr; } static bool partial_match(struct selabel_handle *rec, const char *key) { - struct lookup_result *result = lookup_common(rec, key, 0, true); - bool ret = result; + struct lookup_result buf; - free_lookup_result(result); - return ret; + return !!lookup_common(rec, key, 0, true, &buf); } static struct selabel_lookup_rec *lookup_best_match(struct selabel_handle *rec, @@ -1904,7 +1921,7 @@ static struct selabel_lookup_rec *lookup_best_match(struct selabel_handle *rec, results = calloc(n+1, sizeof(*results)); if (!results) return NULL; - results[0] = lookup_common(rec, key, type, false); + results[0] = lookup_common(rec, key, type, false, NULL); if (results[0]) { if (!results[0]->has_meta_chars) { /* exact match on key */ @@ -1915,7 +1932,7 @@ static struct selabel_lookup_rec *lookup_best_match(struct selabel_handle *rec, prefix_len = results[0]->prefix_len; } for (i = 1; i <= n; i++) { - results[i] = lookup_common(rec, aliases[i-1], type, false); + results[i] = lookup_common(rec, aliases[i-1], type, false, NULL); if (results[i]) { if (!results[i]->has_meta_chars) { /* exact match on alias */ diff --git a/libselinux/src/selinux_internal.h b/libselinux/src/selinux_internal.h index 372837dd..964b8418 100644 --- a/libselinux/src/selinux_internal.h +++ b/libselinux/src/selinux_internal.h @@ -142,4 +142,12 @@ static inline void fclose_errno_safe(FILE *stream) errno = saved_errno; } +#ifdef __GNUC__ +# define likely(x) __builtin_expect(!!(x), 1) +# define unlikely(x) __builtin_expect(!!(x), 0) +#else +# define likely(x) (x) +# define unlikely(x) (x) +#endif /* __GNUC__ */ + #endif /* SELINUX_INTERNAL_H_ */ From patchwork Mon Nov 25 12:08:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Christian_G=C3=B6ttsche?= X-Patchwork-Id: 13884865 Received: from server02.seltendoof.de (server02.seltendoof.de [168.119.48.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4EDFE19146E for ; 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arc=none smtp.client-ip=168.119.48.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=seltendoof.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=seltendoof.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=seltendoof.de header.i=@seltendoof.de header.b="mS8K3d2G" From: =?utf-8?q?Christian_G=C3=B6ttsche?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=seltendoof.de; s=2023072701; t=1732536513; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9rnw6I7U1VGY7u2k08l5bmVtiFwHF6AizdJ7OynI8Fs=; b=mS8K3d2GtnWsRVMyEiAFKgLDFm6sgcTMSFTIJy5a+eQcnhHL/7muuUjpYtJladNY6oB8oe BjIKo5s55EY/lGyhhzveORxTpsQAICCS0reZjJBVlNouOUtNwTVGFo9JcxA2+ya7PLPwP8 p+6caQbgzKKCeU7w4OQy1hPOAowIVCjZsLuO+/uia5IS+8b9b9KeV+mIGlQowJiyffFsS5 M34PlINKxQ1URnzD8+y3Zr4dzyptn8B8gijw98xeue48huv8xzu8dgCsxrxdZvf0kT9NyW QUjJcoEOeY+kH669+c9YrI+YSNBRbK8crzvieQJm90nAW1rU20dy4swHwiKuxA== To: selinux@vger.kernel.org Cc: =?utf-8?q?Christian_G=C3=B6ttsche?= Subject: [PATCH v2 2/3] libselinux: use vector instead of linked list for substitutions Date: Mon, 25 Nov 2024 13:08:26 +0100 Message-ID: <20241125120827.97332-2-cgoettsche@seltendoof.de> In-Reply-To: <20241125120827.97332-1-cgoettsche@seltendoof.de> References: <20241125120827.97332-1-cgoettsche@seltendoof.de> Reply-To: cgzones@googlemail.com Precedence: bulk X-Mailing-List: selinux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Christian Göttsche Utilize cache locality for the substitutions by storing them in contiguous memory instead of a linked list. Signed-off-by: Christian Göttsche --- v2: drop unnecessary check for zero length --- libselinux/src/label_file.c | 127 +++++++++++++++++++----------------- libselinux/src/label_file.h | 20 ++++-- 2 files changed, 80 insertions(+), 67 deletions(-) diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c index 4e212aa4..c91a91f7 100644 --- a/libselinux/src/label_file.c +++ b/libselinux/src/label_file.c @@ -1120,28 +1120,27 @@ static int process_file(const char *path, const char *suffix, return -1; } -static void selabel_subs_fini(struct selabel_sub *ptr) +static void selabel_subs_fini(struct selabel_sub *subs, uint32_t num) { - struct selabel_sub *next; - - while (ptr) { - next = ptr->next; - free(ptr->src); - free(ptr->dst); - free(ptr); - ptr = next; + for (uint32_t i = 0; i < num; i++) { + free(subs[i].src); + free(subs[i].dst); } + + free(subs); } -static char *selabel_sub(const struct selabel_sub *ptr, const char *src) +static char *selabel_apply_subs(const struct selabel_sub *subs, uint32_t num, const char *src) { - char *dst = NULL; - unsigned int len; + char *dst; + uint32_t len; + + for (uint32_t i = 0; i < num; i++) { + const struct selabel_sub *ptr = &subs[i]; - while (ptr) { if (strncmp(src, ptr->src, ptr->slen) == 0 ) { if (src[ptr->slen] == '/' || - src[ptr->slen] == 0) { + src[ptr->slen] == '\0') { if ((src[ptr->slen] == '/') && (strcmp(ptr->dst, "/") == 0)) len = ptr->slen + 1; @@ -1152,34 +1151,38 @@ static char *selabel_sub(const struct selabel_sub *ptr, const char *src) return dst; } } - ptr = ptr->next; } + return NULL; } #if !defined(BUILD_HOST) && !defined(ANDROID) static int selabel_subs_init(const char *path, struct selabel_digest *digest, - struct selabel_sub **out_subs) + struct selabel_sub **out_subs, + uint32_t *out_num, uint32_t *out_alloc) { char buf[1024]; - FILE *cfg = fopen(path, "re"); - struct selabel_sub *list = NULL, *sub = NULL; + FILE *cfg; struct stat sb; - int status = -1; + struct selabel_sub *tmp = NULL; + uint32_t tmp_num = 0, tmp_alloc = 0; + char *src_cpy = NULL, *dst_cpy = NULL; + int rc; *out_subs = NULL; + *out_num = 0; + *out_alloc = 0; + + cfg = fopen(path, "re"); if (!cfg) { /* If the file does not exist, it is not fatal */ return (errno == ENOENT) ? 0 : -1; } - if (fstat(fileno(cfg), &sb) < 0) - goto out; - while (fgets_unlocked(buf, sizeof(buf) - 1, cfg)) { - char *ptr = NULL; + char *ptr; char *src = buf; - char *dst = NULL; + char *dst; size_t len; while (*src && isspace((unsigned char)*src)) @@ -1207,62 +1210,64 @@ static int selabel_subs_init(const char *path, struct selabel_digest *digest, goto err; } - sub = calloc(1, sizeof(*sub)); - if (! sub) + src_cpy = strdup(src); + if (!src_cpy) goto err; - sub->src = strdup(src); - if (! sub->src) + dst_cpy = strdup(dst); + if (!dst_cpy) goto err; - sub->dst = strdup(dst); - if (! sub->dst) + rc = GROW_ARRAY(tmp); + if (rc) goto err; - sub->slen = len; - sub->next = list; - list = sub; - sub = NULL; + tmp[tmp_num++] = (struct selabel_sub) { + .src = src_cpy, + .slen = len, + .dst = dst_cpy, + }; + src_cpy = NULL; + dst_cpy = NULL; } + rc = fstat(fileno(cfg), &sb); + if (rc < 0) + goto err; + if (digest_add_specfile(digest, cfg, NULL, sb.st_size, path) < 0) goto err; - *out_subs = list; - status = 0; + *out_subs = tmp; + *out_num = tmp_num; + *out_alloc = tmp_alloc; -out: fclose(cfg); - return status; + + return 0; + err: - if (sub) - free(sub->src); - free(sub); - while (list) { - sub = list->next; - free(list->src); - free(list->dst); - free(list); - list = sub; - } - goto out; + free(dst_cpy); + free(src_cpy); + free(tmp); + fclose_errno_safe(cfg); + return -1; } #endif static char *selabel_sub_key(const struct saved_data *data, const char *key) { - char *ptr = NULL; - char *dptr = NULL; + char *ptr, *dptr; - ptr = selabel_sub(data->subs, key); + ptr = selabel_apply_subs(data->subs, data->subs_num, key); if (ptr) { - dptr = selabel_sub(data->dist_subs, ptr); + dptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, ptr); if (dptr) { free(ptr); ptr = dptr; } } else { - ptr = selabel_sub(data->dist_subs, key); + ptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, key); } return ptr; @@ -1307,23 +1312,25 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts, if (!path) { status = selabel_subs_init( selinux_file_context_subs_dist_path(), - rec->digest, &data->dist_subs); + rec->digest, + &data->dist_subs, &data->dist_subs_num, &data->dist_subs_alloc); if (status) goto finish; status = selabel_subs_init(selinux_file_context_subs_path(), - rec->digest, &data->subs); + rec->digest, + &data->subs, &data->subs_num, &data->subs_alloc); if (status) goto finish; path = selinux_file_context_path(); } else { snprintf(subs_file, sizeof(subs_file), "%s.subs_dist", path); status = selabel_subs_init(subs_file, rec->digest, - &data->dist_subs); + &data->dist_subs, &data->dist_subs_num, &data->dist_subs_alloc); if (status) goto finish; snprintf(subs_file, sizeof(subs_file), "%s.subs", path); status = selabel_subs_init(subs_file, rec->digest, - &data->subs); + &data->subs, &data->subs_num, &data->subs_alloc); if (status) goto finish; } @@ -1391,8 +1398,8 @@ static void closef(struct selabel_handle *rec) if (!data) return; - selabel_subs_fini(data->subs); - selabel_subs_fini(data->dist_subs); + selabel_subs_fini(data->subs, data->subs_num); + selabel_subs_fini(data->dist_subs, data->dist_subs_num); free_spec_node(data->root); free(data->root); diff --git a/libselinux/src/label_file.h b/libselinux/src/label_file.h index de8190f9..436982bf 100644 --- a/libselinux/src/label_file.h +++ b/libselinux/src/label_file.h @@ -67,11 +67,11 @@ extern struct lookup_result *lookup_all(struct selabel_handle *rec, const char * extern enum selabel_cmp_result cmp(const struct selabel_handle *h1, const struct selabel_handle *h2); #endif /* FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */ +/* A path substitution entry */ struct selabel_sub { - char *src; - unsigned int slen; - char *dst; - struct selabel_sub *next; + char *src; /* source path prefix */ + char *dst; /* substituted path prefix */ + uint32_t slen; /* length of source path prefix */ }; /* A regular expression file security context specification */ @@ -159,9 +159,17 @@ struct saved_data { struct mmap_area *mmap_areas; - /* substitution support */ + /* + * Array of distribution substitutions + */ struct selabel_sub *dist_subs; + uint32_t dist_subs_num, dist_subs_alloc; + + /* + * Array of local substitutions + */ struct selabel_sub *subs; + uint32_t subs_num, subs_alloc; }; static inline mode_t string_to_file_kind(const char *mode) @@ -811,8 +819,6 @@ static int insert_spec(const struct selabel_handle *rec, struct saved_data *data return 0; } -#undef GROW_ARRAY - static inline void free_spec_node(struct spec_node *node) { for (uint32_t i = 0; i < node->literal_specs_num; i++) { From patchwork Mon Nov 25 12:08:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Christian_G=C3=B6ttsche?= X-Patchwork-Id: 13884866 Received: from server02.seltendoof.de (server02.seltendoof.de [168.119.48.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 88B7A194147 for ; 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Signed-off-by: Christian Göttsche --- v2: add patch --- libselinux/src/label_file.c | 38 +++++++++++++++++++++++++------------ libselinux/src/label_file.h | 1 + 2 files changed, 27 insertions(+), 12 deletions(-) diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c index c91a91f7..523968a6 100644 --- a/libselinux/src/label_file.c +++ b/libselinux/src/label_file.c @@ -1130,9 +1130,9 @@ static void selabel_subs_fini(struct selabel_sub *subs, uint32_t num) free(subs); } -static char *selabel_apply_subs(const struct selabel_sub *subs, uint32_t num, const char *src) +static char *selabel_apply_subs(const struct selabel_sub *subs, uint32_t num, const char *src, size_t slen) { - char *dst; + char *dst, *tmp; uint32_t len; for (uint32_t i = 0; i < num; i++) { @@ -1146,8 +1146,14 @@ static char *selabel_apply_subs(const struct selabel_sub *subs, uint32_t num, co len = ptr->slen + 1; else len = ptr->slen; - if (asprintf(&dst, "%s%s", ptr->dst, &src[len]) < 0) + + dst = malloc(ptr->dlen + slen - len + 1); + if (!dst) return NULL; + + tmp = mempcpy(dst, ptr->dst, ptr->dlen); + tmp = mempcpy(tmp, &src[len], slen - len); + *tmp = '\0'; return dst; } } @@ -1183,7 +1189,7 @@ static int selabel_subs_init(const char *path, struct selabel_digest *digest, char *ptr; char *src = buf; char *dst; - size_t len; + size_t slen, dlen; while (*src && isspace((unsigned char)*src)) src++; @@ -1204,8 +1210,14 @@ static int selabel_subs_init(const char *path, struct selabel_digest *digest, if (! *dst) continue; - len = strlen(src); - if (len >= UINT32_MAX) { + slen = strlen(src); + if (slen >= UINT32_MAX) { + errno = EINVAL; + goto err; + } + + dlen = strlen(dst); + if (dlen >= UINT32_MAX) { errno = EINVAL; goto err; } @@ -1224,8 +1236,9 @@ static int selabel_subs_init(const char *path, struct selabel_digest *digest, tmp[tmp_num++] = (struct selabel_sub) { .src = src_cpy, - .slen = len, + .slen = slen, .dst = dst_cpy, + .dlen = dlen, }; src_cpy = NULL; dst_cpy = NULL; @@ -1255,19 +1268,19 @@ err: } #endif -static char *selabel_sub_key(const struct saved_data *data, const char *key) +static char *selabel_sub_key(const struct saved_data *data, const char *key, size_t key_len) { char *ptr, *dptr; - ptr = selabel_apply_subs(data->subs, data->subs_num, key); + ptr = selabel_apply_subs(data->subs, data->subs_num, key, key_len); if (ptr) { - dptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, ptr); + dptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, ptr, strlen(ptr)); if (dptr) { free(ptr); ptr = dptr; } } else { - ptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, key); + ptr = selabel_apply_subs(data->dist_subs, data->dist_subs_num, key, key_len); } return ptr; @@ -1783,9 +1796,10 @@ FUZZ_EXTERN struct lookup_result *lookup_all(struct selabel_handle *rec, clean_key[len - 1] = '\0'; key = clean_key; + len--; } - sub = selabel_sub_key(data, key); + sub = selabel_sub_key(data, key, len); if (sub) key = sub; diff --git a/libselinux/src/label_file.h b/libselinux/src/label_file.h index 436982bf..122894a2 100644 --- a/libselinux/src/label_file.h +++ b/libselinux/src/label_file.h @@ -72,6 +72,7 @@ struct selabel_sub { char *src; /* source path prefix */ char *dst; /* substituted path prefix */ uint32_t slen; /* length of source path prefix */ + uint32_t dlen; /* length of substituted path prefix */ }; /* A regular expression file security context specification */