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authorGONG, Ruiqi <gongruiqi1@huawei.com>2022-10-19 10:57:10 +0800
committerPaul Moore <paul@paul-moore.com>2022-10-19 09:55:53 -0400
commitabe3c631447dcd1ba7af972fe6f054bee6f136fa (patch)
tree18195112f8c26e0f9a61f02c90ffad90e4e613fd /security
parent9abf2313adc1ca1b6180c508c25f22f9395cc780 (diff)
selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context()
The following warning was triggered on a hardware environment: SELinux: Converting 162 SID table entries... BUG: sleeping function called from invalid context at __might_sleep+0x60/0x74 0x0 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1 Call trace: dump_backtrace+0x0/0x1c8 show_stack+0x18/0x28 dump_stack+0xe8/0x15c ___might_sleep+0x168/0x17c __might_sleep+0x60/0x74 __kmalloc_track_caller+0xa0/0x7dc kstrdup+0x54/0xac convert_context+0x48/0x2e4 sidtab_context_to_sid+0x1c4/0x36c security_context_to_sid_core+0x168/0x238 security_context_to_sid_default+0x14/0x24 inode_doinit_use_xattr+0x164/0x1e4 inode_doinit_with_dentry+0x1c0/0x488 selinux_d_instantiate+0x20/0x34 security_d_instantiate+0x70/0xbc d_splice_alias+0x4c/0x3c0 ext4_lookup+0x1d8/0x200 [ext4] __lookup_slow+0x12c/0x1e4 walk_component+0x100/0x200 path_lookupat+0x88/0x118 filename_lookup+0x98/0x130 user_path_at_empty+0x48/0x60 vfs_statx+0x84/0x140 vfs_fstatat+0x20/0x30 __se_sys_newfstatat+0x30/0x74 __arm64_sys_newfstatat+0x1c/0x2c el0_svc_common.constprop.0+0x100/0x184 do_el0_svc+0x1c/0x2c el0_svc+0x20/0x34 el0_sync_handler+0x80/0x17c el0_sync+0x13c/0x140 SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is not valid (left unmapped). It was found that within a critical section of spin_lock_irqsave in sidtab_context_to_sid(), convert_context() (hooked by sidtab_convert_params.func) might cause the process to sleep via allocating memory with GFP_KERNEL, which is problematic. As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL. Therefore, fix this problem by adding a gfp_t argument for convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC properly in individual callers. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20221018120111.1474581-1-gongruiqi1@huawei.com/ [1] Reported-by: Tan Ninghao <tanninghao1@huawei.com> Fixes: ee1a84fdfeed ("selinux: overhaul sidtab to fix bug and improve performance") Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com> Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com> [PM: wrap long BUG() output lines, tweak subject line] Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/ss/services.c5
-rw-r--r--security/selinux/ss/sidtab.c4
-rw-r--r--security/selinux/ss/sidtab.h2
3 files changed, 6 insertions, 5 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index fe5fcf571c56..64a6a37dc36d 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2022,7 +2022,8 @@ static inline int convert_context_handle_invalid_context(
* in `newc'. Verify that the context is valid
* under the new policy.
*/
-static int convert_context(struct context *oldc, struct context *newc, void *p)
+static int convert_context(struct context *oldc, struct context *newc, void *p,
+ gfp_t gfp_flags)
{
struct convert_context_args *args;
struct ocontext *oc;
@@ -2036,7 +2037,7 @@ static int convert_context(struct context *oldc, struct context *newc, void *p)
args = p;
if (oldc->str) {
- s = kstrdup(oldc->str, GFP_KERNEL);
+ s = kstrdup(oldc->str, gfp_flags);
if (!s)
return -ENOMEM;
diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index a54b8652bfb5..db5cce385bf8 100644
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -325,7 +325,7 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
}
rc = convert->func(context, &dst_convert->context,
- convert->args);
+ convert->args, GFP_ATOMIC);
if (rc) {
context_destroy(&dst->context);
goto out_unlock;
@@ -404,7 +404,7 @@ static int sidtab_convert_tree(union sidtab_entry_inner *edst,
while (i < SIDTAB_LEAF_ENTRIES && *pos < count) {
rc = convert->func(&esrc->ptr_leaf->entries[i].context,
&edst->ptr_leaf->entries[i].context,
- convert->args);
+ convert->args, GFP_KERNEL);
if (rc)
return rc;
(*pos)++;
diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
index 4eff0e49dcb2..9fce0d553fe2 100644
--- a/security/selinux/ss/sidtab.h
+++ b/security/selinux/ss/sidtab.h
@@ -65,7 +65,7 @@ struct sidtab_isid_entry {
};
struct sidtab_convert_params {
- int (*func)(struct context *oldc, struct context *newc, void *args);
+ int (*func)(struct context *oldc, struct context *newc, void *args, gfp_t gfp_flags);
void *args;
struct sidtab *target;
};