From: Norbert Szetei <norbert@doyensec.com> mainline inclusion from mainline-v6.15-rc1 commit beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC1QQK CVE: CVE-2025-22039 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The dacloffset field was originally typed as int and used in an unchecked addition, which could overflow and bypass the existing bounds check in both smb_check_perm_dacl() and smb_inherit_dacl(). This could result in out-of-bounds memory access and a kernel crash when dereferencing the DACL pointer. This patch converts dacloffset to unsigned int and uses check_add_overflow() to validate access to the DACL. Cc: stable@vger.kernel.org Signed-off-by: Norbert Szetei <norbert@doyensec.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Conflicts: fs/smb/server/smbacl.c [Just context differences.] Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/smb/server/smbacl.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c index 1c9775f1efa5..0038aed5333e 100644 --- a/fs/smb/server/smbacl.c +++ b/fs/smb/server/smbacl.c @@ -1007,7 +1007,9 @@ int smb_inherit_dacl(struct ksmbd_conn *conn, struct dentry *parent = path->dentry->d_parent; struct mnt_idmap *idmap = mnt_idmap(path->mnt); int inherited_flags = 0, flags = 0, i, ace_cnt = 0, nt_size = 0, pdacl_size; - int rc = 0, num_aces, dacloffset, pntsd_type, pntsd_size, acl_len, aces_size; + int rc = 0, num_aces, pntsd_type, pntsd_size, acl_len, aces_size; + unsigned int dacloffset; + size_t dacl_struct_end; char *aces_base; bool is_dir = S_ISDIR(d_inode(path->dentry)->i_mode); @@ -1015,8 +1017,11 @@ int smb_inherit_dacl(struct ksmbd_conn *conn, parent, &parent_pntsd); if (pntsd_size <= 0) return -ENOENT; + dacloffset = le32_to_cpu(parent_pntsd->dacloffset); - if (!dacloffset || (dacloffset + sizeof(struct smb_acl) > pntsd_size)) { + if (!dacloffset || + check_add_overflow(dacloffset, sizeof(struct smb_acl), &dacl_struct_end) || + dacl_struct_end > (size_t)pntsd_size) { rc = -EINVAL; goto free_parent_pntsd; } @@ -1219,7 +1224,9 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path, struct smb_ntsd *pntsd = NULL; struct smb_acl *pdacl; struct posix_acl *posix_acls; - int rc = 0, pntsd_size, acl_size, aces_size, pdacl_size, dacl_offset; + int rc = 0, pntsd_size, acl_size, aces_size, pdacl_size; + unsigned int dacl_offset; + size_t dacl_struct_end; struct smb_sid sid; int granted = le32_to_cpu(*pdaccess & ~FILE_MAXIMAL_ACCESS_LE); struct smb_ace *ace; @@ -1238,7 +1245,8 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path, dacl_offset = le32_to_cpu(pntsd->dacloffset); if (!dacl_offset || - (dacl_offset + sizeof(struct smb_acl) > pntsd_size)) + check_add_overflow(dacl_offset, sizeof(struct smb_acl), &dacl_struct_end) || + dacl_struct_end > (size_t)pntsd_size) goto err_out; pdacl = (struct smb_acl *)((char *)pntsd + le32_to_cpu(pntsd->dacloffset)); -- 2.39.2