Date: Sat, 01 Jan 2022 00:41:16 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 259071] Read past EoF in NFS client and fusefs Message-ID: <bug-259071-227-nUZmlrt1RL@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-259071-227@https.bugs.freebsd.org/bugzilla/> References: <bug-259071-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D259071 --- Comment #22 from commit-hook@FreeBSD.org --- A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=3D13d593a5b060cf7be40acfa2ca9dc9e0e= 2339a31 commit 13d593a5b060cf7be40acfa2ca9dc9e0e2339a31 Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2021-11-29 02:17:34 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2022-01-01 00:38:42 +0000 Fix a race in fusefs that can corrupt a file's size. VOPs like VOP_SETATTR can change a file's size, with the vnode exclusively locked. But VOPs like VOP_LOOKUP look up the file size from the server without the vnode locked. So a race is possible. For example: 1) One thread calls VOP_SETATTR to truncate a file. It locks the vnode and sends FUSE_SETATTR to the server. 2) A second thread calls VOP_LOOKUP and fetches the file's attributes f= rom the server. Then it blocks trying to acquire the vnode lock. 3) FUSE_SETATTR returns and the first thread releases the vnode lock. 4) The second thread acquires the vnode lock and caches the file's attributes, which are now out-of-date. Fix this race by recording a timestamp in the vnode of the last time that its filesize was modified. Check that timestamp during VOP_LOOKUP and VFS_VGET. If it's newer than the time at which FUSE_LOOKUP was issued to the server, ignore the attributes returned by FUSE_LOOKUP. PR: 259071 Reported by: Agata <chogata@moosefs.pro> Reviewed by: pfg MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D33158 sys/fs/fuse/fuse_internal.c | 5 + sys/fs/fuse/fuse_io.c | 5 +- sys/fs/fuse/fuse_node.c | 5 +- sys/fs/fuse/fuse_node.h | 6 + sys/fs/fuse/fuse_vfsops.c | 13 +- sys/fs/fuse/fuse_vnops.c | 21 +- tests/sys/fs/fusefs/Makefile | 1 + tests/sys/fs/fusefs/last_local_modify.cc (new) | 469 +++++++++++++++++++++= ++++ 8 files changed, 516 insertions(+), 9 deletions(-) --=20 You are receiving this mail because: You are the assignee for the bug.=
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