* [PATCH RESEND] apparmor: replace sprintf with snprintf in aa_new_learning_profile
@ 2025-11-22 11:54 Thorsten Blum
2025-11-27 1:34 ` John Johansen
0 siblings, 1 reply; 2+ messages in thread
From: Thorsten Blum @ 2025-11-22 11:54 UTC (permalink / raw)
To: John Johansen, Paul Moore, James Morris, Serge E. Hallyn
Cc: Thorsten Blum, apparmor, linux-security-module, linux-kernel
Replace unbounded sprintf() calls with snprintf() to prevent potential
buffer overflows in aa_new_learning_profile(). While the current code
works correctly, snprintf() is safer and follows secure coding best
practices. No functional changes.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
security/apparmor/policy.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 50d5345ff5cb..b09323867fea 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -697,24 +697,27 @@ struct aa_profile *aa_new_learning_profile(struct aa_profile *parent, bool hat,
struct aa_profile *p, *profile;
const char *bname;
char *name = NULL;
+ size_t name_sz;
AA_BUG(!parent);
if (base) {
- name = kmalloc(strlen(parent->base.hname) + 8 + strlen(base),
- gfp);
+ name_sz = strlen(parent->base.hname) + 8 + strlen(base);
+ name = kmalloc(name_sz, gfp);
if (name) {
- sprintf(name, "%s//null-%s", parent->base.hname, base);
+ snprintf(name, name_sz, "%s//null-%s",
+ parent->base.hname, base);
goto name;
}
/* fall through to try shorter uniq */
}
- name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, gfp);
+ name_sz = strlen(parent->base.hname) + 2 + 7 + 8;
+ name = kmalloc(name_sz, gfp);
if (!name)
return NULL;
- sprintf(name, "%s//null-%x", parent->base.hname,
- atomic_inc_return(&parent->ns->uniq_null));
+ snprintf(name, name_sz, "%s//null-%x", parent->base.hname,
+ atomic_inc_return(&parent->ns->uniq_null));
name:
/* lookup to see if this is a dup creation */
--
2.51.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH RESEND] apparmor: replace sprintf with snprintf in aa_new_learning_profile
2025-11-22 11:54 [PATCH RESEND] apparmor: replace sprintf with snprintf in aa_new_learning_profile Thorsten Blum
@ 2025-11-27 1:34 ` John Johansen
0 siblings, 0 replies; 2+ messages in thread
From: John Johansen @ 2025-11-27 1:34 UTC (permalink / raw)
To: Thorsten Blum, Paul Moore, James Morris, Serge E. Hallyn
Cc: apparmor, linux-security-module, linux-kernel
On 11/22/25 03:54, Thorsten Blum wrote:
> Replace unbounded sprintf() calls with snprintf() to prevent potential
> buffer overflows in aa_new_learning_profile(). While the current code
> works correctly, snprintf() is safer and follows secure coding best
> practices. No functional changes.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
I have pulled this into my tree
Acked-by: John Johansen <john.johansen@canonical.com>
> ---
> security/apparmor/policy.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
> index 50d5345ff5cb..b09323867fea 100644
> --- a/security/apparmor/policy.c
> +++ b/security/apparmor/policy.c
> @@ -697,24 +697,27 @@ struct aa_profile *aa_new_learning_profile(struct aa_profile *parent, bool hat,
> struct aa_profile *p, *profile;
> const char *bname;
> char *name = NULL;
> + size_t name_sz;
>
> AA_BUG(!parent);
>
> if (base) {
> - name = kmalloc(strlen(parent->base.hname) + 8 + strlen(base),
> - gfp);
> + name_sz = strlen(parent->base.hname) + 8 + strlen(base);
> + name = kmalloc(name_sz, gfp);
> if (name) {
> - sprintf(name, "%s//null-%s", parent->base.hname, base);
> + snprintf(name, name_sz, "%s//null-%s",
> + parent->base.hname, base);
> goto name;
> }
> /* fall through to try shorter uniq */
> }
>
> - name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, gfp);
> + name_sz = strlen(parent->base.hname) + 2 + 7 + 8;
> + name = kmalloc(name_sz, gfp);
> if (!name)
> return NULL;
> - sprintf(name, "%s//null-%x", parent->base.hname,
> - atomic_inc_return(&parent->ns->uniq_null));
> + snprintf(name, name_sz, "%s//null-%x", parent->base.hname,
> + atomic_inc_return(&parent->ns->uniq_null));
>
> name:
> /* lookup to see if this is a dup creation */
^ permalink raw reply [flat|nested] 2+ messages in thread
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