* [PATCH] smb: client: Use snprintf in cifs_set_cifscreds
@ 2026-02-26 22:15 Thorsten Blum
2026-02-26 23:26 ` Steve French
2026-02-27 15:03 ` Paulo Alcantara
0 siblings, 2 replies; 3+ messages in thread
From: Thorsten Blum @ 2026-02-26 22:15 UTC (permalink / raw)
To: Steve French, Paulo Alcantara, Ronnie Sahlberg, Shyam Prasad N,
Tom Talpey, Bharath SM
Cc: Thorsten Blum, linux-cifs, samba-technical, linux-kernel
Replace unbounded sprintf() calls with the safer snprintf(). Avoid using
magic numbers and use strlen() to calculate the key descriptor buffer
size. Save the size in a local variable and reuse it for the bounded
snprintf() calls. Remove CIFSCREDS_DESC_SIZE.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
fs/smb/client/connect.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 33dfe116ca52..a055496c4835 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -2167,9 +2167,6 @@ void __cifs_put_smb_ses(struct cifs_ses *ses)
#ifdef CONFIG_KEYS
-/* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
-#define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
-
/* Populate username and pw fields from keyring if possible */
static int
cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
@@ -2177,6 +2174,7 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
int rc = 0;
int is_domain = 0;
const char *delim, *payload;
+ size_t desc_sz;
char *desc;
ssize_t len;
struct key *key;
@@ -2185,7 +2183,9 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
struct sockaddr_in6 *sa6;
const struct user_key_payload *upayload;
- desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
+ /* "cifs:a:" and "cifs:d:" are the same length; +1 for NUL terminator */
+ desc_sz = strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1;
+ desc = kmalloc(desc_sz, GFP_KERNEL);
if (!desc)
return -ENOMEM;
@@ -2193,11 +2193,11 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
switch (server->dstaddr.ss_family) {
case AF_INET:
sa = (struct sockaddr_in *)&server->dstaddr;
- sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
+ snprintf(desc, desc_sz, "cifs:a:%pI4", &sa->sin_addr.s_addr);
break;
case AF_INET6:
sa6 = (struct sockaddr_in6 *)&server->dstaddr;
- sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
+ snprintf(desc, desc_sz, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
break;
default:
cifs_dbg(FYI, "Bad ss_family (%hu)\n",
@@ -2216,7 +2216,7 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
}
/* didn't work, try to find a domain key */
- sprintf(desc, "cifs:d:%s", ses->domainName);
+ snprintf(desc, desc_sz, "cifs:d:%s", ses->domainName);
cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
key = request_key(&key_type_logon, desc, "");
if (IS_ERR(key)) {
--
Thorsten Blum <thorsten.blum@linux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6 9D84 7336 78FD 8DFE EAD4
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] smb: client: Use snprintf in cifs_set_cifscreds
2026-02-26 22:15 [PATCH] smb: client: Use snprintf in cifs_set_cifscreds Thorsten Blum
@ 2026-02-26 23:26 ` Steve French
2026-02-27 15:03 ` Paulo Alcantara
1 sibling, 0 replies; 3+ messages in thread
From: Steve French @ 2026-02-26 23:26 UTC (permalink / raw)
To: Thorsten Blum
Cc: Steve French, Paulo Alcantara, Ronnie Sahlberg, Shyam Prasad N,
Tom Talpey, Bharath SM, linux-cifs, samba-technical,
linux-kernel
merged into cifs-2.6.git for-next pending additional review and testing
On Thu, Feb 26, 2026 at 4:16 PM Thorsten Blum <thorsten.blum@linux.dev> wrote:
>
> Replace unbounded sprintf() calls with the safer snprintf(). Avoid using
> magic numbers and use strlen() to calculate the key descriptor buffer
> size. Save the size in a local variable and reuse it for the bounded
> snprintf() calls. Remove CIFSCREDS_DESC_SIZE.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> fs/smb/client/connect.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
> index 33dfe116ca52..a055496c4835 100644
> --- a/fs/smb/client/connect.c
> +++ b/fs/smb/client/connect.c
> @@ -2167,9 +2167,6 @@ void __cifs_put_smb_ses(struct cifs_ses *ses)
>
> #ifdef CONFIG_KEYS
>
> -/* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
> -#define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
> -
> /* Populate username and pw fields from keyring if possible */
> static int
> cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
> @@ -2177,6 +2174,7 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
> int rc = 0;
> int is_domain = 0;
> const char *delim, *payload;
> + size_t desc_sz;
> char *desc;
> ssize_t len;
> struct key *key;
> @@ -2185,7 +2183,9 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
> struct sockaddr_in6 *sa6;
> const struct user_key_payload *upayload;
>
> - desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
> + /* "cifs:a:" and "cifs:d:" are the same length; +1 for NUL terminator */
> + desc_sz = strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1;
> + desc = kmalloc(desc_sz, GFP_KERNEL);
> if (!desc)
> return -ENOMEM;
>
> @@ -2193,11 +2193,11 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
> switch (server->dstaddr.ss_family) {
> case AF_INET:
> sa = (struct sockaddr_in *)&server->dstaddr;
> - sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
> + snprintf(desc, desc_sz, "cifs:a:%pI4", &sa->sin_addr.s_addr);
> break;
> case AF_INET6:
> sa6 = (struct sockaddr_in6 *)&server->dstaddr;
> - sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
> + snprintf(desc, desc_sz, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
> break;
> default:
> cifs_dbg(FYI, "Bad ss_family (%hu)\n",
> @@ -2216,7 +2216,7 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
> }
>
> /* didn't work, try to find a domain key */
> - sprintf(desc, "cifs:d:%s", ses->domainName);
> + snprintf(desc, desc_sz, "cifs:d:%s", ses->domainName);
> cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
> key = request_key(&key_type_logon, desc, "");
> if (IS_ERR(key)) {
> --
> Thorsten Blum <thorsten.blum@linux.dev>
> GPG: 1D60 735E 8AEF 3BE4 73B6 9D84 7336 78FD 8DFE EAD4
>
>
--
Thanks,
Steve
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] smb: client: Use snprintf in cifs_set_cifscreds
2026-02-26 22:15 [PATCH] smb: client: Use snprintf in cifs_set_cifscreds Thorsten Blum
2026-02-26 23:26 ` Steve French
@ 2026-02-27 15:03 ` Paulo Alcantara
1 sibling, 0 replies; 3+ messages in thread
From: Paulo Alcantara @ 2026-02-27 15:03 UTC (permalink / raw)
To: Thorsten Blum, Steve French, Ronnie Sahlberg, Shyam Prasad N,
Tom Talpey, Bharath SM
Cc: Thorsten Blum, linux-cifs, samba-technical, linux-kernel
Thorsten Blum <thorsten.blum@linux.dev> writes:
> Replace unbounded sprintf() calls with the safer snprintf(). Avoid using
> magic numbers and use strlen() to calculate the key descriptor buffer
> size. Save the size in a local variable and reuse it for the bounded
> snprintf() calls. Remove CIFSCREDS_DESC_SIZE.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> fs/smb/client/connect.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-02-26 23:26 ` Steve French
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