diff options
| author | Nathan Lynch <nathanl@linux.ibm.com> | 2023-08-10 22:37:55 -0500 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-08-17 09:46:14 +1000 |
| commit | 4f3175979e62de3b929bfa54a0db4b87d36257a7 (patch) | |
| tree | 11912dc76f3d37c3729bf021991da1cdf6849fdd | |
| parent | 86582e6189dd8f9f52c25d46c70fe5d111da6345 (diff) | |
powerpc/rtas_flash: allow user copy to flash block cache objects
With hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the
/proc/powerpc/rtas/firmware_update interface to prepare a system
firmware update yields a BUG():
kernel BUG at mm/usercopy.c:102!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2
Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries
NIP: c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000
REGS: c0000000148c76a0 TRAP: 0700 Not tainted (6.5.0-rc3+)
MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 24002242 XER: 0000000c
CFAR: c0000000001fbd34 IRQMASK: 0
[ ... GPRs omitted ... ]
NIP usercopy_abort+0xa0/0xb0
LR usercopy_abort+0x9c/0xb0
Call Trace:
usercopy_abort+0x9c/0xb0 (unreliable)
__check_heap_object+0x1b4/0x1d0
__check_object_size+0x2d0/0x380
rtas_flash_write+0xe4/0x250
proc_reg_write+0xfc/0x160
vfs_write+0xfc/0x4e0
ksys_write+0x90/0x160
system_call_exception+0x178/0x320
system_call_common+0x160/0x2c4
The blocks of the firmware image are copied directly from user memory
to objects allocated from flash_block_cache, so flash_block_cache must
be created using kmem_cache_create_usercopy() to mark it safe for user
access.
Fixes: 6d07d1cd300f ("usercopy: Restrict non-usercopy caches to size 0")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[mpe: Trim and indent oops]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230810-rtas-flash-vs-hardened-usercopy-v2-1-dcf63793a938@linux.ibm.com
| -rw-r--r-- | arch/powerpc/kernel/rtas_flash.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c index 4caf5e3079eb..359577ec1680 100644 --- a/arch/powerpc/kernel/rtas_flash.c +++ b/arch/powerpc/kernel/rtas_flash.c @@ -709,9 +709,9 @@ static int __init rtas_flash_init(void) if (!rtas_validate_flash_data.buf) return -ENOMEM; - flash_block_cache = kmem_cache_create("rtas_flash_cache", - RTAS_BLK_SIZE, RTAS_BLK_SIZE, 0, - NULL); + flash_block_cache = kmem_cache_create_usercopy("rtas_flash_cache", + RTAS_BLK_SIZE, RTAS_BLK_SIZE, + 0, 0, RTAS_BLK_SIZE, NULL); if (!flash_block_cache) { printk(KERN_ERR "%s: failed to create block cache\n", __func__); |