From f505a45776d149632e3bd0b87f0da1609607161a Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Thu, 26 Feb 2026 23:15:22 +0100 Subject: [PATCH] smb: client: Use snprintf in cifs_set_cifscreds 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 Acked-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French --- 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 4c34d9603e05..3bad2c5c523d 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)) {