CVE-2022-50699

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context()<br /> <br /> The following warning was triggered on a hardware environment:<br /> <br /> SELinux: Converting 162 SID table entries...<br /> BUG: sleeping function called from invalid context at<br /> __might_sleep+0x60/0x74 0x0<br /> in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar<br /> CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1<br /> Call trace:<br /> dump_backtrace+0x0/0x1c8<br /> show_stack+0x18/0x28<br /> dump_stack+0xe8/0x15c<br /> ___might_sleep+0x168/0x17c<br /> __might_sleep+0x60/0x74<br /> __kmalloc_track_caller+0xa0/0x7dc<br /> kstrdup+0x54/0xac<br /> convert_context+0x48/0x2e4<br /> sidtab_context_to_sid+0x1c4/0x36c<br /> security_context_to_sid_core+0x168/0x238<br /> security_context_to_sid_default+0x14/0x24<br /> inode_doinit_use_xattr+0x164/0x1e4<br /> inode_doinit_with_dentry+0x1c0/0x488<br /> selinux_d_instantiate+0x20/0x34<br /> security_d_instantiate+0x70/0xbc<br /> d_splice_alias+0x4c/0x3c0<br /> ext4_lookup+0x1d8/0x200 [ext4]<br /> __lookup_slow+0x12c/0x1e4<br /> walk_component+0x100/0x200<br /> path_lookupat+0x88/0x118<br /> filename_lookup+0x98/0x130<br /> user_path_at_empty+0x48/0x60<br /> vfs_statx+0x84/0x140<br /> vfs_fstatat+0x20/0x30<br /> __se_sys_newfstatat+0x30/0x74<br /> __arm64_sys_newfstatat+0x1c/0x2c<br /> el0_svc_common.constprop.0+0x100/0x184<br /> do_el0_svc+0x1c/0x2c<br /> el0_svc+0x20/0x34<br /> el0_sync_handler+0x80/0x17c<br /> el0_sync+0x13c/0x140<br /> SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is<br /> not valid (left unmapped).<br /> <br /> It was found that within a critical section of spin_lock_irqsave in<br /> sidtab_context_to_sid(), convert_context() (hooked by<br /> sidtab_convert_params.func) might cause the process to sleep via<br /> allocating memory with GFP_KERNEL, which is problematic.<br /> <br /> As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func<br /> has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL.<br /> Therefore, fix this problem by adding a gfp_t argument for<br /> convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC<br /> properly in individual callers.<br /> <br /> [PM: wrap long BUG() output lines, tweak subject line]