From: Pali Rohár pali@kernel.org
mainline inclusion from mainline-v6.10-rc2 commit e2a8910af01653c1c268984855629d71fb81f404 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRA3 CVE: CVE-2024-49996
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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ReparseDataLength is sum of the InodeType size and DataBuffer size. So to get DataBuffer size it is needed to subtract InodeType's size from ReparseDataLength.
Function cifs_strndup_from_utf16() is currentlly accessing buf->DataBuffer at position after the end of the buffer because it does not subtract InodeType size from the length. Fix this problem and correctly subtract variable len.
Member InodeType is present only when reparse buffer is large enough. Check for ReparseDataLength before accessing InodeType to prevent another invalid memory access.
Major and minor rdev values are present also only when reparse buffer is large enough. Check for reparse buffer size before calling reparse_mkdev().
Fixes: d5ecebc4900d ("smb3: Allow query of symlinks stored as reparse points") Reviewed-by: Paulo Alcantara (Red Hat) pc@manguebit.com Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Long Li leo.lilong@huawei.com --- fs/smb/client/reparse.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c index 1fba8116567d..455aa8cc5ec4 100644 --- a/fs/smb/client/reparse.c +++ b/fs/smb/client/reparse.c @@ -320,9 +320,16 @@ static int parse_reparse_posix(struct reparse_posix_data *buf, unsigned int len; u64 type;
+ len = le16_to_cpu(buf->ReparseDataLength); + if (len < sizeof(buf->InodeType)) { + cifs_dbg(VFS, "srv returned malformed nfs buffer\n"); + return -EIO; + } + + len -= sizeof(buf->InodeType); + switch ((type = le64_to_cpu(buf->InodeType))) { case NFS_SPECFILE_LNK: - len = le16_to_cpu(buf->ReparseDataLength); data->symlink_target = cifs_strndup_from_utf16(buf->DataBuffer, len, true, cifs_sb->local_nls); @@ -482,12 +489,18 @@ bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb, u32 tag = data->reparse.tag;
if (tag == IO_REPARSE_TAG_NFS && buf) { + if (le16_to_cpu(buf->ReparseDataLength) < sizeof(buf->InodeType)) + return false; switch (le64_to_cpu(buf->InodeType)) { case NFS_SPECFILE_CHR: + if (le16_to_cpu(buf->ReparseDataLength) != sizeof(buf->InodeType) + 8) + return false; fattr->cf_mode |= S_IFCHR; fattr->cf_rdev = reparse_mkdev(buf->DataBuffer); break; case NFS_SPECFILE_BLK: + if (le16_to_cpu(buf->ReparseDataLength) != sizeof(buf->InodeType) + 8) + return false; fattr->cf_mode |= S_IFBLK; fattr->cf_rdev = reparse_mkdev(buf->DataBuffer); break;