| Message ID | 20200717174309.1164575-3-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce partial kernel_read_file() support | expand |
On 2020-07-17 10:42 a.m., Kees Cook wrote: > FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs > that are interested in filtering between types of things. The "how" > should be an internal detail made uninteresting to the LSMs. > > Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") > Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") > Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") > Cc: stable@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Scott Branden <scott.branden@broadcom.com> > --- > To aid in backporting, this change is made before moving > kernel_read_file() to separate header/source files. > --- > drivers/base/firmware_loader/main.c | 5 ++--- > fs/exec.c | 7 ++++--- > include/linux/fs.h | 2 +- > kernel/module.c | 2 +- > security/integrity/digsig.c | 2 +- > security/integrity/ima/ima_fs.c | 2 +- > security/integrity/ima/ima_main.c | 6 ++---- > 7 files changed, 12 insertions(+), 14 deletions(-) > > diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c > index ca871b13524e..c2f57cedcd6f 100644 > --- a/drivers/base/firmware_loader/main.c > +++ b/drivers/base/firmware_loader/main.c > @@ -465,14 +465,12 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > int i, len; > int rc = -ENOENT; > char *path; > - enum kernel_read_file_id id = READING_FIRMWARE; > size_t msize = INT_MAX; > void *buffer = NULL; > > /* Already populated data member means we're loading into a buffer */ > if (!decompress && fw_priv->data) { > buffer = fw_priv->data; > - id = READING_FIRMWARE_PREALLOC_BUFFER; > msize = fw_priv->allocated_size; > } > > @@ -496,7 +494,8 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > > /* load firmware files from the mount namespace of init */ > rc = kernel_read_file_from_path_initns(path, &buffer, > - &size, msize, id); > + &size, msize, > + READING_FIRMWARE); > if (rc) { > if (rc != -ENOENT) > dev_warn(device, "loading %s failed with error %d\n", > diff --git a/fs/exec.c b/fs/exec.c > index e6e8a9a70327..2bf549757ce7 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -927,6 +927,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > { > loff_t i_size, pos; > ssize_t bytes = 0; > + void *allocated = NULL; > int ret; > > if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) > @@ -950,8 +951,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > goto out; > } > > - if (id != READING_FIRMWARE_PREALLOC_BUFFER) > - *buf = vmalloc(i_size); > + if (!*buf) > + *buf = allocated = vmalloc(i_size); > if (!*buf) { > ret = -ENOMEM; > goto out; > @@ -980,7 +981,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > > out_free: > if (ret < 0) { > - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { > + if (allocated) { > vfree(*buf); > *buf = NULL; > } > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 3f881a892ea7..95fc775ed937 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2993,10 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode) > #endif > extern int do_pipe_flags(int *, int); > > +/* This is a list of *what* is being read, not *how*. */ > #define __kernel_read_file_id(id) \ > id(UNKNOWN, unknown) \ > id(FIRMWARE, firmware) \ > - id(FIRMWARE_PREALLOC_BUFFER, firmware) \ > id(FIRMWARE_EFI_EMBEDDED, firmware) \ > id(MODULE, kernel-module) \ > id(KEXEC_IMAGE, kexec-image) \ > diff --git a/kernel/module.c b/kernel/module.c > index 0c6573b98c36..26105148f4d2 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -3988,7 +3988,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) > { > struct load_info info = { }; > loff_t size; > - void *hdr; > + void *hdr = NULL; > int err; > > err = may_init_module(); > diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c > index e9cbadade74b..ac02b7632353 100644 > --- a/security/integrity/digsig.c > +++ b/security/integrity/digsig.c > @@ -169,7 +169,7 @@ int __init integrity_add_key(const unsigned int id, const void *data, > > int __init integrity_load_x509(const unsigned int id, const char *path) > { > - void *data; > + void *data = NULL; > loff_t size; > int rc; > key_perm_t perm; > diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c > index e3fcad871861..15a44c5022f7 100644 > --- a/security/integrity/ima/ima_fs.c > +++ b/security/integrity/ima/ima_fs.c > @@ -272,7 +272,7 @@ static const struct file_operations ima_ascii_measurements_ops = { > > static ssize_t ima_read_policy(char *path) > { > - void *data; > + void *data = NULL; > char *datap; > loff_t size; > int rc, pathlen = strlen(path); > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index c1583d98c5e5..f80ee4ce4669 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -611,19 +611,17 @@ void ima_post_path_mknod(struct dentry *dentry) > int ima_read_file(struct file *file, enum kernel_read_file_id read_id) > { > /* > - * READING_FIRMWARE_PREALLOC_BUFFER > - * > * Do devices using pre-allocated memory run the risk of the > * firmware being accessible to the device prior to the completion > * of IMA's signature verification any more than when using two > - * buffers? > + * buffers? It may be desirable to include the buffer address > + * in this API and walk all the dma_map_single() mappings to check. > */ > return 0; > } > > const int read_idmap[READING_MAX_ID] = { > [READING_FIRMWARE] = FIRMWARE_CHECK, > - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK, > [READING_MODULE] = MODULE_CHECK, > [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, > [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index ca871b13524e..c2f57cedcd6f 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -465,14 +465,12 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, int i, len; int rc = -ENOENT; char *path; - enum kernel_read_file_id id = READING_FIRMWARE; size_t msize = INT_MAX; void *buffer = NULL; /* Already populated data member means we're loading into a buffer */ if (!decompress && fw_priv->data) { buffer = fw_priv->data; - id = READING_FIRMWARE_PREALLOC_BUFFER; msize = fw_priv->allocated_size; } @@ -496,7 +494,8 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, /* load firmware files from the mount namespace of init */ rc = kernel_read_file_from_path_initns(path, &buffer, - &size, msize, id); + &size, msize, + READING_FIRMWARE); if (rc) { if (rc != -ENOENT) dev_warn(device, "loading %s failed with error %d\n", diff --git a/fs/exec.c b/fs/exec.c index e6e8a9a70327..2bf549757ce7 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -927,6 +927,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, { loff_t i_size, pos; ssize_t bytes = 0; + void *allocated = NULL; int ret; if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) @@ -950,8 +951,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, goto out; } - if (id != READING_FIRMWARE_PREALLOC_BUFFER) - *buf = vmalloc(i_size); + if (!*buf) + *buf = allocated = vmalloc(i_size); if (!*buf) { ret = -ENOMEM; goto out; @@ -980,7 +981,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, out_free: if (ret < 0) { - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { + if (allocated) { vfree(*buf); *buf = NULL; } diff --git a/include/linux/fs.h b/include/linux/fs.h index 3f881a892ea7..95fc775ed937 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2993,10 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode) #endif extern int do_pipe_flags(int *, int); +/* This is a list of *what* is being read, not *how*. */ #define __kernel_read_file_id(id) \ id(UNKNOWN, unknown) \ id(FIRMWARE, firmware) \ - id(FIRMWARE_PREALLOC_BUFFER, firmware) \ id(FIRMWARE_EFI_EMBEDDED, firmware) \ id(MODULE, kernel-module) \ id(KEXEC_IMAGE, kexec-image) \ diff --git a/kernel/module.c b/kernel/module.c index 0c6573b98c36..26105148f4d2 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3988,7 +3988,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) { struct load_info info = { }; loff_t size; - void *hdr; + void *hdr = NULL; int err; err = may_init_module(); diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index e9cbadade74b..ac02b7632353 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -169,7 +169,7 @@ int __init integrity_add_key(const unsigned int id, const void *data, int __init integrity_load_x509(const unsigned int id, const char *path) { - void *data; + void *data = NULL; loff_t size; int rc; key_perm_t perm; diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index e3fcad871861..15a44c5022f7 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -272,7 +272,7 @@ static const struct file_operations ima_ascii_measurements_ops = { static ssize_t ima_read_policy(char *path) { - void *data; + void *data = NULL; char *datap; loff_t size; int rc, pathlen = strlen(path); diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index c1583d98c5e5..f80ee4ce4669 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -611,19 +611,17 @@ void ima_post_path_mknod(struct dentry *dentry) int ima_read_file(struct file *file, enum kernel_read_file_id read_id) { /* - * READING_FIRMWARE_PREALLOC_BUFFER - * * Do devices using pre-allocated memory run the risk of the * firmware being accessible to the device prior to the completion * of IMA's signature verification any more than when using two - * buffers? + * buffers? It may be desirable to include the buffer address + * in this API and walk all the dma_map_single() mappings to check. */ return 0; } const int read_idmap[READING_MAX_ID] = { [READING_FIRMWARE] = FIRMWARE_CHECK, - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK, [READING_MODULE] = MODULE_CHECK, [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs that are interested in filtering between types of things. The "how" should be an internal detail made uninteresting to the LSMs. Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- To aid in backporting, this change is made before moving kernel_read_file() to separate header/source files. --- drivers/base/firmware_loader/main.c | 5 ++--- fs/exec.c | 7 ++++--- include/linux/fs.h | 2 +- kernel/module.c | 2 +- security/integrity/digsig.c | 2 +- security/integrity/ima/ima_fs.c | 2 +- security/integrity/ima/ima_main.c | 6 ++---- 7 files changed, 12 insertions(+), 14 deletions(-)