diff options
| author | Vineet Gupta <Vineet.Gupta1@synopsys.com> | 2016-08-19 12:10:02 -0700 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-09-13 17:49:41 -0400 |
| commit | 05d9d0b96e53c52a113fd783c0c97c830c8dc7af (patch) | |
| tree | 82f26a603d8512b102bc91cb2013c906df209619 | |
| parent | 8ae95ed4ae5fc7c3391ed668b2014c9e2079533b (diff) | |
ARC: uaccess: get_user to zero out dest in cause of fault
Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.
Verified using following
| {
| u32 bogus1 = 0xdeadbeef;
| u64 bogus2 = 0xdead;
| int rc1, rc2;
|
| pr_info("Orig values %x %llx\n", bogus1, bogus2);
| rc1 = get_user(bogus1, (u32 __user *)0x40000000);
| rc2 = get_user(bogus2, (u64 __user *)0x50000000);
| pr_info("access %d %d, new values %x %llx\n",
| rc1, rc2, bogus1, bogus2);
| }
| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | arch/arc/include/asm/uaccess.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h index a78d5670884f..41faf17cd28d 100644 --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h @@ -83,7 +83,10 @@ "2: ;nop\n" \ " .section .fixup, \"ax\"\n" \ " .align 4\n" \ - "3: mov %0, %3\n" \ + "3: # return -EFAULT\n" \ + " mov %0, %3\n" \ + " # zero out dst ptr\n" \ + " mov %1, 0\n" \ " j 2b\n" \ " .previous\n" \ " .section __ex_table, \"a\"\n" \ @@ -101,7 +104,11 @@ "2: ;nop\n" \ " .section .fixup, \"ax\"\n" \ " .align 4\n" \ - "3: mov %0, %3\n" \ + "3: # return -EFAULT\n" \ + " mov %0, %3\n" \ + " # zero out dst ptr\n" \ + " mov %1, 0\n" \ + " mov %R1, 0\n" \ " j 2b\n" \ " .previous\n" \ " .section __ex_table, \"a\"\n" \ |