From: Namjae Jeon linkinjeon@kernel.org
[ Upstream commit eeb827f2922eb07ffbf7d53569cc95b38272646f ]
cifs.ko is missing validation check when accessing smb_aces. This patch add validation check for the fields in smb_aces.
Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/smb/client/cifsacl.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/smb/client/cifsacl.c b/fs/smb/client/cifsacl.c index 64bd68f750f84..f9d577f2d59bb 100644 --- a/fs/smb/client/cifsacl.c +++ b/fs/smb/client/cifsacl.c @@ -811,7 +811,23 @@ static void parse_dacl(struct smb_acl *pdacl, char *end_of_acl, return;
for (i = 0; i < num_aces; ++i) { + if (end_of_acl - acl_base < acl_size) + break; + ppace[i] = (struct smb_ace *) (acl_base + acl_size); + acl_base = (char *)ppace[i]; + acl_size = offsetof(struct smb_ace, sid) + + offsetof(struct smb_sid, sub_auth); + + if (end_of_acl - acl_base < acl_size || + ppace[i]->sid.num_subauth == 0 || + ppace[i]->sid.num_subauth > SID_MAX_SUB_AUTHORITIES || + (end_of_acl - acl_base < + acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth) || + (le16_to_cpu(ppace[i]->size) < + acl_size + sizeof(__le32) * ppace[i]->sid.num_subauth)) + break; + #ifdef CONFIG_CIFS_DEBUG2 dump_ace(ppace[i], end_of_acl); #endif @@ -855,7 +871,6 @@ static void parse_dacl(struct smb_acl *pdacl, char *end_of_acl, (void *)ppace[i], sizeof(struct smb_ace)); */
- acl_base = (char *)ppace[i]; acl_size = le16_to_cpu(ppace[i]->size); }