This is a note to let you know that I've just added the patch titled get_rock_ridge_filename(): handle malformed NM entries to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: get_rock_ridge_filename-handle-malformed-nm-entries.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 99d825822eade8d827a1817357cbf3f889a552d6 Mon Sep 17 00:00:00 2001 From: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Date: Thu, 5 May 2016 16:25:35 -0400 Subject: get_rock_ridge_filename(): handle malformed NM entries From: Al Viro <viro@xxxxxxxxxxxxxxxxxx> commit 99d825822eade8d827a1817357cbf3f889a552d6 upstream. Payloads of NM entries are not supposed to contain NUL. When we run into such, only the part prior to the first NUL goes into the concatenation (i.e. the directory entry name being encoded by a bunch of NM entries). We do stop when the amount collected so far + the claimed amount in the current NM entry exceed 254. So far, so good, but what we return as the total length is the sum of *claimed* sizes, not the actual amount collected. And that can grow pretty large - not unlimited, since you'd need to put CE entries in between to be able to get more than the maximum that could be contained in one isofs directory entry / continuation chunk and we are stop once we'd encountered 32 CEs, but you can get about 8Kb easily. And that's what will be passed to readdir callback as the name length. 8Kb __copy_to_user() from a buffer allocated by __get_free_page() Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/isofs/rock.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) --- a/fs/isofs/rock.c +++ b/fs/isofs/rock.c @@ -203,6 +203,8 @@ int get_rock_ridge_filename(struct iso_d int retnamlen = 0; int truncate = 0; int ret = 0; + char *p; + int len; if (!ISOFS_SB(inode->i_sb)->s_rock) return 0; @@ -267,12 +269,17 @@ repeat: rr->u.NM.flags); break; } - if ((strlen(retname) + rr->len - 5) >= 254) { + len = rr->len - 5; + if (retnamlen + len >= 254) { truncate = 1; break; } - strncat(retname, rr->u.NM.name, rr->len - 5); - retnamlen += rr->len - 5; + p = memchr(rr->u.NM.name, '\0', len); + if (unlikely(p)) + len = p - rr->u.NM.name; + memcpy(retname + retnamlen, rr->u.NM.name, len); + retnamlen += len; + retname[retnamlen] = '\0'; break; case SIG('R', 'E'): kfree(rs.buffer); Patches currently in stable-queue which might be from viro@xxxxxxxxxxxxxxxxxx are queue-4.4/get_rock_ridge_filename-handle-malformed-nm-entries.patch queue-4.4/atomic_open-fix-the-handling-of-create_error.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html