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| author | Thiago Rafael Becker <thiago.becker@gmail.com> | 2017-12-14 15:33:12 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-12-14 16:00:49 -0800 |
| commit | bdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758 (patch) | |
| tree | 942b1b8fa9b1e52503d5f9894d43674255813566 /kernel/groups.c | |
| parent | 1f704fd0d14043e76e80f6b8b2251b9b2cedcca6 (diff) | |
| download | lwn-bdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758.tar.gz lwn-bdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758.zip | |
kernel: make groups_sort calling a responsibility group_info allocators
In testing, we found that nfsd threads may call set_groups in parallel
for the same entry cached in auth.unix.gid, racing in the call of
groups_sort, corrupting the groups for that entry and leading to
permission denials for the client.
This patch:
- Make groups_sort globally visible.
- Move the call to groups_sort to the modifiers of group_info
- Remove the call to groups_sort from set_groups
Link: http://lkml.kernel.org/r/20171211151420.18655-1-thiago.becker@gmail.com
Signed-off-by: Thiago Rafael Becker <thiago.becker@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/groups.c')
| -rw-r--r-- | kernel/groups.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/groups.c b/kernel/groups.c index e357bc800111..daae2f2dc6d4 100644 --- a/kernel/groups.c +++ b/kernel/groups.c @@ -86,11 +86,12 @@ static int gid_cmp(const void *_a, const void *_b) return gid_gt(a, b) - gid_lt(a, b); } -static void groups_sort(struct group_info *group_info) +void groups_sort(struct group_info *group_info) { sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid), gid_cmp, NULL); } +EXPORT_SYMBOL(groups_sort); /* a simple bsearch */ int groups_search(const struct group_info *group_info, kgid_t grp) @@ -122,7 +123,6 @@ int groups_search(const struct group_info *group_info, kgid_t grp) void set_groups(struct cred *new, struct group_info *group_info) { put_group_info(new->group_info); - groups_sort(group_info); get_group_info(group_info); new->group_info = group_info; } @@ -206,6 +206,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist) return retval; } + groups_sort(group_info); retval = set_current_groups(group_info); put_group_info(group_info); |