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authorOndrej Mosnacek <omosnace@redhat.com>2019-06-12 11:12:26 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-26 10:14:07 +0300
commit914026d581007a67a911630a0a8afebdbe7d41d3 (patch)
tree3861a4bb44904fc67f4e65cc138ed147fa8c5d36 /security
parent10e3788e6575e370c63f3f6aa501b19c3b5aa9f6 (diff)
downloadlinux-914026d581007a67a911630a0a8afebdbe7d41d3.tar.xz
selinux: fix empty write to keycreate file
[ Upstream commit 464c258aa45b09f16aa0f05847ed8895873262d9 ] When sid == 0 (we are resetting keycreate_sid to the default value), we should skip the KEY__CREATE check. Before this patch, doing a zero-sized write to /proc/self/keycreate would check if the current task can create unlabeled keys (which would usually fail with -EACCESS and generate an AVC). Now it skips the check and correctly sets the task's keycreate_sid to 0. Bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1719067 Tested using the reproducer from the report above. Fixes: 4eb582cf1fbd ("[PATCH] keys: add a way to store the appropriate context for newly-created keys") Reported-by: Kir Kolyshkin <kir@sacred.ru> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 70bad15ed7a0..109ab510bdb1 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6550,11 +6550,12 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
} else if (!strcmp(name, "fscreate")) {
tsec->create_sid = sid;
} else if (!strcmp(name, "keycreate")) {
- error = avc_has_perm(&selinux_state,
- mysid, sid, SECCLASS_KEY, KEY__CREATE,
- NULL);
- if (error)
- goto abort_change;
+ if (sid) {
+ error = avc_has_perm(&selinux_state, mysid, sid,
+ SECCLASS_KEY, KEY__CREATE, NULL);
+ if (error)
+ goto abort_change;
+ }
tsec->keycreate_sid = sid;
} else if (!strcmp(name, "sockcreate")) {
tsec->sockcreate_sid = sid;