3.18-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter dan.carpenter@oracle.com
commit 8ad8aa353524d89fa2e09522f3078166ff78ec42 upstream.
The "old_entry + le32_to_cpu(pDirInfo->NextEntryOffset)" can wrap around so I have added a check for integer overflow.
Reported-by: Dr Silvio Cesare of InfoSect silvio.cesare@gmail.com Reviewed-by: Ronnie Sahlberg lsahlber@redhat.com Reviewed-by: Aurelien Aptel aaptel@suse.com Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Steve French stfrench@microsoft.com CC: Stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/readdir.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -366,8 +366,15 @@ static char *nxt_dir_entry(char *old_ent
new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) + pfData->FileNameLength; - } else - new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset); + } else { + u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset); + + if (old_entry + next_offset < old_entry) { + cifs_dbg(VFS, "invalid offset %u\n", next_offset); + return NULL; + } + new_entry = old_entry + next_offset; + } cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry); /* validate that new_entry is not past end of SMB */ if (new_entry >= end_of_smb) {