Messages in this thread Patch in this message | | | From | Willy Tarreau <> | Subject | [PATCH 3.10 081/319] ARC: uaccess: get_user to zero out dest in cause of fault | Date | Sun, 5 Feb 2017 20:21:08 +0100 |
| |
From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
commit 05d9d0b96e53c52a113fd783c0c97c830c8dc7af upstream.
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 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Willy Tarreau <w@1wt.eu> --- arch/arc/include/asm/uaccess.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h index 30c9baf..08770c7 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" \ -- 2.8.0.rc2.1.gbe9624a
| |