diff options
| author | Marco Elver <elver@google.com> | 2021-11-26 13:47:46 +0100 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2021-11-30 15:13:47 -0800 |
| commit | 52d0b8b18776f184c53632c5e0068201491cdb61 (patch) | |
| tree | 0ac74f38355bcceb2129e296f23f4a57db9088e3 /arch/x86/kernel/fpu | |
| parent | 7d697f0d5737768fa1039b8953b67c08d8d406d1 (diff) | |
x86/fpu/signal: Initialize sw_bytes in save_xstate_epilog()
save_sw_bytes() did not fully initialize sw_bytes, which caused KMSAN
to report an infoleak (see below).
Initialize sw_bytes explicitly to avoid this.
KMSAN report follows:
=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user ./include/linux/instrumented.h:121
BUG: KMSAN: kernel-infoleak in __copy_to_user ./include/linux/uaccess.h:154
BUG: KMSAN: kernel-infoleak in save_xstate_epilog+0x2df/0x510 arch/x86/kernel/fpu/signal.c:127
instrument_copy_to_user ./include/linux/instrumented.h:121
__copy_to_user ./include/linux/uaccess.h:154
save_xstate_epilog+0x2df/0x510 arch/x86/kernel/fpu/signal.c:127
copy_fpstate_to_sigframe+0x861/0xb60 arch/x86/kernel/fpu/signal.c:245
get_sigframe+0x656/0x7e0 arch/x86/kernel/signal.c:296
__setup_rt_frame+0x14d/0x2a60 arch/x86/kernel/signal.c:471
setup_rt_frame arch/x86/kernel/signal.c:781
handle_signal arch/x86/kernel/signal.c:825
arch_do_signal_or_restart+0x417/0xdd0 arch/x86/kernel/signal.c:870
handle_signal_work kernel/entry/common.c:149
exit_to_user_mode_loop+0x1f6/0x490 kernel/entry/common.c:173
exit_to_user_mode_prepare kernel/entry/common.c:208
__syscall_exit_to_user_mode_work kernel/entry/common.c:290
syscall_exit_to_user_mode+0x7e/0xc0 kernel/entry/common.c:302
do_syscall_64+0x60/0xd0 arch/x86/entry/common.c:88
entry_SYSCALL_64_after_hwframe+0x44/0xae ??:?
Local variable sw_bytes created at:
save_xstate_epilog+0x80/0x510 arch/x86/kernel/fpu/signal.c:121
copy_fpstate_to_sigframe+0x861/0xb60 arch/x86/kernel/fpu/signal.c:245
Bytes 20-47 of 48 are uninitialized
Memory access of size 48 starts at ffff8880801d3a18
Data copied to user address 00007ffd90e2ef50
=====================================================
Link: https://lore.kernel.org/all/CAG_fn=V9T6OKPonSjsi9PmWB0hMHFC=yawozdft8i1-MSxrv=w@mail.gmail.com/
Fixes: 53599b4d54b9b8dd ("x86/fpu/signal: Prepare for variable sigframe length")
Reported-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lkml.kernel.org/r/20211126124746.761278-1-glider@google.com
Diffstat (limited to 'arch/x86/kernel/fpu')
| -rw-r--r-- | arch/x86/kernel/fpu/signal.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index d5958278eba6..91d4b6de58ab 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -118,7 +118,7 @@ static inline bool save_xstate_epilog(void __user *buf, int ia32_frame, struct fpstate *fpstate) { struct xregs_state __user *x = buf; - struct _fpx_sw_bytes sw_bytes; + struct _fpx_sw_bytes sw_bytes = {}; u32 xfeatures; int err; |