| Message ID | 20210222151231.22572-7-romain.perier@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Manual replacement of all strlcpy in favor of strscpy | expand |
On Mon, 2021-02-22 at 16:12 +0100, Romain Perier wrote: > The strlcpy() reads the entire source buffer first, it is dangerous if > the source buffer lenght is unbounded or possibility non NULL-terminated. As other's have pointed out, "lenght" -> length. > It can lead to linear read overflows, crashes, etc... > > As recommended in the deprecated interfaces [1], it should be replaced > by strscpy. > > This commit replaces all calls to strlcpy that handle the return values > by the corresponding strscpy calls with new handling of the return > values (as it is quite different between the two functions). > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > > Signed-off-by: Romain Perier <romain.perier@gmail.com> > --- > security/integrity/ima/ima_policy.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > index 9b45d064a87d..1a905b8b064f 100644 > --- a/security/integrity/ima/ima_policy.c > +++ b/security/integrity/ima/ima_policy.c > @@ -790,8 +790,14 @@ static int __init ima_init_arch_policy(void) > for (rules = arch_rules, i = 0; *rules != NULL; rules++) { > char rule[255]; > int result; > + ssize_t len; > > - result = strlcpy(rule, *rules, sizeof(rule)); > + len = strscpy(rule, *rules, sizeof(rule)); > + if (len == -E2BIG) { > + pr_warn("Internal copy of architecture policy rule '%s' " > + "failed. Skipping.\n", *rules); "arch_rules" is an array of hard coded strings. The generic reason for replacing strlcpy with strscpy doesn't seem applicable; however, the additonal warning is appropriate. (User-visible strings are not bound to the 80 column length. Breaking up the line like this is fine, but unnecessary.) Acked-by: Mimi Zohar <zohar@linux.ibm.com> thanks, Mimi > + continue; > + } > > INIT_LIST_HEAD(&arch_policy_entry[i].list); > result = ima_parse_rule(rule, &arch_policy_entry[i]); >
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 9b45d064a87d..1a905b8b064f 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -790,8 +790,14 @@ static int __init ima_init_arch_policy(void) for (rules = arch_rules, i = 0; *rules != NULL; rules++) { char rule[255]; int result; + ssize_t len; - result = strlcpy(rule, *rules, sizeof(rule)); + len = strscpy(rule, *rules, sizeof(rule)); + if (len == -E2BIG) { + pr_warn("Internal copy of architecture policy rule '%s' " + "failed. Skipping.\n", *rules); + continue; + } INIT_LIST_HEAD(&arch_policy_entry[i].list); result = ima_parse_rule(rule, &arch_policy_entry[i]);
The strlcpy() reads the entire source buffer first, it is dangerous if the source buffer lenght is unbounded or possibility non NULL-terminated. It can lead to linear read overflows, crashes, etc... As recommended in the deprecated interfaces [1], it should be replaced by strscpy. This commit replaces all calls to strlcpy that handle the return values by the corresponding strscpy calls with new handling of the return values (as it is quite different between the two functions). [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy Signed-off-by: Romain Perier <romain.perier@gmail.com> --- security/integrity/ima/ima_policy.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)