The patch titled
initramfs: prevent buffer overflow when unpacking to rootfs
has been added to the -mm tree. Its filename is
initramfs-prevent-buffer-overflow-when-unpacking-to-rootfs.patch
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------------------------------------------------------
Subject: initramfs: prevent buffer overflow when unpacking to rootfs
From: Aaro Koskinen <aaro.koskinen@xxxxxx>
Garbage in the initrd memory area may result in the unpack routine
accessing memory outside the buffer. The patch adds a check that the
specified area size is not exceeded.
The patch prevents the following kernel panic on Amstrad E3:
Unpacking initramfs...
Unable to handle kernel paging request at virtual address c20121a7
pgd = c0004000
[c20121a7] *pgd=00000000
Internal error: Oops: 75 [#1] PREEMPT
last sysfs file:
Modules linked in:
CPU: 0 Not tainted (2.6.34-rc2-00052-gae6be51 #19)
PC is at unpack_to_rootfs+0xac/0x33c
LR is at decompress_method+0x28/0x64
pc : [<c0009858>] lr : [<c015fcc4>] psr: 20000013
sp : c1819f68 ip : 00000000 fp : c0023b88
r10: c20121a7 r9 : c0023b98 r8 : 00000000
r7 : 00300000 r6 : fffede59 r5 : c0023ad8 r4 : 00000000
r3 : 00000000 r2 : 00000001 r1 : c0303034 r0 : 00000000
Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 0000317f Table: 10004000 DAC: 00000017
Process swapper (pid: 1, stack limit = 0xc1818270)
Stack: (0xc1819f68 to 0xc181a000)
9f60: 00000000 c03f77ec c00092f8 c03f68fc 00000000 c03f77e0
9f80: c00228fc 00000000 c000a3c8 00000000 00000000 c03f77e0 c00228fc 00000000
9fa0: c000a3c8 00000001 00000000 00000000 00000000 c000a410 c002263c c00283b0
9fc0: 00000000 00000170 c03da678 00000000 c002263c c00228fc 00000000 00000000
9fe0: 00000000 c0008594 00000000 00000000 00000000 c0029f74 8d7cf20a a7ca85e0
[<c0009858>] (unpack_to_rootfs+0xac/0x33c) from [<c000a410>] (populate_rootfs+0x48/0xb0)
[<c000a410>] (populate_rootfs+0x48/0xb0) from [<c00283b0>] (do_one_initcall+0x60/0x1c0)
[<c00283b0>] (do_one_initcall+0x60/0x1c0) from [<c0008594>] (kernel_init+0xa8/0x15c)
[<c0008594>] (kernel_init+0xa8/0x15c) from [<c0029f74>] (kernel_thread_exit+0x0/0x8)
Code: e1a05001 e1a09000 e1a0b00c ea000059 (e5da3000)
---[ end trace da227214a82491b7 ]---
Kernel panic - not syncing: Attempted to kill init!
[<c002e56c>] (unwind_backtrace+0x0/0xec) from [<c02f1a40>] (panic+0x40/0xcc)
[<c02f1a40>] (panic+0x40/0xcc) from [<c004af64>] (do_exit+0x60/0x608)
[<c004af64>] (do_exit+0x60/0x608) from [<c002c8d4>] (die+0x1b4/0x1e4)
[<c002c8d4>] (die+0x1b4/0x1e4) from [<c002f7d8>] (__do_kernel_fault+0x64/0x84)
[<c002f7d8>] (__do_kernel_fault+0x64/0x84) from [<c002fac8>] (do_translation_fault+0x70/0x80)
[<c002fac8>] (do_translation_fault+0x70/0x80) from [<c00282f0>] (do_DataAbort+0x34/0x94)
[<c00282f0>] (do_DataAbort+0x34/0x94) from [<c0028ac0>] (__dabt_svc+0x40/0x60)
Exception stack(0xc1819f20 to 0xc1819f68)
9f20: 00000000 c0303034 00000001 00000000 00000000 c0023ad8 fffede59 00300000
9f40: 00000000 c0023b98 c20121a7 c0023b88 00000000 c1819f68 c015fcc4 c0009858
9f60: 20000013 ffffffff
[<c0028ac0>] (__dabt_svc+0x40/0x60) from [<c0009858>] (unpack_to_rootfs+0xac/0x33c)
[<c0009858>] (unpack_to_rootfs+0xac/0x33c) from [<c000a410>] (populate_rootfs+0x48/0xb0)
[<c000a410>] (populate_rootfs+0x48/0xb0) from [<c00283b0>] (do_one_initcall+0x60/0x1c0)
[<c00283b0>] (do_one_initcall+0x60/0x1c0) from [<c0008594>] (kernel_init+0xa8/0x15c)
[<c0008594>] (kernel_init+0xa8/0x15c) from [<c0029f74>] (kernel_thread_exit+0x0/0x8)
Signed-off-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/initramfs.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN init/initramfs.c~initramfs-prevent-buffer-overflow-when-unpacking-to-rootfs init/initramfs.c
--- a/init/initramfs.c~initramfs-prevent-buffer-overflow-when-unpacking-to-rootfs
+++ a/init/initramfs.c
@@ -460,6 +460,8 @@ static char * __init unpack_to_rootfs(ch
}
if (state != Reset)
error("junk in compressed archive");
+ if (my_inptr >= len)
+ break;
this_header = saved_offset + my_inptr;
buf += my_inptr;
len -= my_inptr;
_
Patches currently in -mm which might be from aaro.koskinen@xxxxxx are
initramfs-prevent-buffer-overflow-when-unpacking-to-rootfs.patch
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