[U-Boot] [U-Boot, v2, 10/10] gpt: harden set_gpt_info() against non NULL-terminated strings

Tom Rini
2017-08-07T13:55:22Z

On Tue, Jul 04, 2017 at 11:19:46AM -0700, Alison Chaiken wrote:

> From: Alison Chaiken <alison@peloton-tech.com>
>
> Strings read from devices may sometimes fail to be
> NULL-terminated. The functions in lib/string.c are subject to
> failure in this case. Protect against observed failures in
> set_gpt_info() by switching to length-checking variants with a length
> limit of the maximum possible partition table length. At the same
> time, add a few checks for NULL string pointers.
>
> Here is an example as observed in sandbox under GDB:
>
> => gpt verify host 0 $partitions
> Program received signal SIGSEGV, Segmentation fault.
> 0x0000000000477747 in strlen (s=0x0) at lib/string.c:267
> 267 for (sc = s; *sc != '\0'; ++sc)
> (gdb) bt
> #0 0x0000000000477747 in strlen (s=0x0) at lib/string.c:267
> #1 0x00000000004140b2 in set_gpt_info (str_part=<optimized out>,
> str_disk_guid=str_disk_guid at entry=0x7fffffffdbe8, partitions=partitions at entry=0x7fffffffdbd8,
> parts_count=parts_count at entry=0x7fffffffdbcf "", dev_desc=<optimized out>) at cmd/gpt.c:415
> #2 0x00000000004145b9 in gpt_verify (str_part=<optimized out>, blk_dev_desc=0x7fffef09a9d0) at cmd/gpt.c:580
> #3 do_gpt (cmdtp=<optimized out>, flag=<optimized out>, argc=<optimized out>, argv=0x7fffef09a8f0)
> at cmd/gpt.c:783
> #4 0x00000000004295b0 in cmd_call (argv=0x7fffef09a8f0, argc=0x5, flag=<optimized out>,
> cmdtp=0x714e20 <_u_boot_list_2_cmd_2_gpt>) at common/command.c:500
> #5 cmd_process (flag=<optimized out>, argc=0x5, argv=0x7fffef09a8f0,
> repeatable=repeatable at entry=0x726c04 <flag_repeat>, ticks=ticks at entry=0x0) at common/command.c:539
>
> Suggested-by: Lothar WaÃŸmann <LW@karo-electronics.de>
> Signed-off-by: Alison Chaiken <alison@peloton-tech.com>

Applied to u-boot/master, thanks!

--
Tom
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