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| author | Vitaly Chikunov <vt@altlinux.org> | 2022-02-16 21:18:21 +0300 |
|---|---|---|
| committer | Christian Schoenebeck <qemu_oss@crudebyte.com> | 2022-02-17 16:57:58 +0100 |
| commit | e64e27d5cb103b7764f1a05b6eda7e7fedd517c5 (patch) | |
| tree | 6f349f7536e1b2e9ee569f7363b9802e82fb8e20 /hw/9pfs/9p-synth.h | |
| parent | 494fbbd3ed46a14ef0924651c058b9b0dcb4a7b4 (diff) | |
| download | qemu-e64e27d5cb103b7764f1a05b6eda7e7fedd517c5.zip qemu-e64e27d5cb103b7764f1a05b6eda7e7fedd517c5.tar.gz qemu-e64e27d5cb103b7764f1a05b6eda7e7fedd517c5.tar.bz2 | |
9pfs: Fix segfault in do_readdir_many caused by struct dirent overread
`struct dirent' returned from readdir(3) could be shorter (or longer)
than `sizeof(struct dirent)', thus memcpy of sizeof length will overread
into unallocated page causing SIGSEGV. Example stack trace:
#0 0x00005555559ebeed v9fs_co_readdir_many (/usr/bin/qemu-system-x86_64 + 0x497eed)
#1 0x00005555559ec2e9 v9fs_readdir (/usr/bin/qemu-system-x86_64 + 0x4982e9)
#2 0x0000555555eb7983 coroutine_trampoline (/usr/bin/qemu-system-x86_64 + 0x963983)
#3 0x00007ffff73e0be0 n/a (n/a + 0x0)
While fixing this, provide a helper for any future `struct dirent' cloning.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/841
Cc: qemu-stable@nongnu.org
Co-authored-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Tested-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Acked-by: Greg Kurz <groug@kaod.org>
Tested-by: Vitaly Chikunov <vt@altlinux.org>
Message-Id: <20220216181821.3481527-1-vt@altlinux.org>
[C.S. - Fix typo in source comment. ]
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Diffstat (limited to 'hw/9pfs/9p-synth.h')
| -rw-r--r-- | hw/9pfs/9p-synth.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/hw/9pfs/9p-synth.h b/hw/9pfs/9p-synth.h index 036d7e4..eeb246f 100644 --- a/hw/9pfs/9p-synth.h +++ b/hw/9pfs/9p-synth.h @@ -41,6 +41,11 @@ typedef struct V9fsSynthOpenState { off_t offset; V9fsSynthNode *node; struct dirent dent; + /* + * Ensure there is enough space for 'dent' above, some systems have a + * d_name size of just 1, which would cause a buffer overrun. + */ + char dent_trailing_space[NAME_MAX]; } V9fsSynthOpenState; int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode, |