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ia64: Fix memchr for large input sizes (BZ #22603)

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Current optimized ia64 memchr uses a strategy to check for last address
by adding the input one with expected size.  However it does not take
care for possible overflow.

It was triggered by 3038145ca23 where default rawmemchr now uses memchr
(p, c, (size_t)-1).

This patch fixes it by implement a satured addition where overflows
sets the maximum pointer size to UINTPTR_MAX.

Checked on ia64-linux-gnu where it fixes both stratcliff and
test-rawmemchr failures.

	Adhemerval Zanella  <adhemerval.zanella@linaro.org>
	James Clarke <jrtc27@jrtc27.com>

	[BZ #22603]
	* sysdeps/ia64/memchr.S (__memchr): Avoid overflow in pointer
	addition.

(cherry picked from commit 3bb1ef58b989012f8199b82af6ec136da2f9fda3)
This commit is contained in:
Adhemerval Zanella 2017-12-14 09:05:46 -02:00 committed by Aurelien Jarno
parent 989f59db39
commit 268bd5f053
2 changed files with 11 additions and 0 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2017-12-19 Adhemerval Zanella <adhemerval.zanella@linaro.org>
James Clarke <jrtc27@jrtc27.com>
[BZ #22603]
* sysdeps/ia64/memchr.S (__memchr): Avoid overflow in pointer
addition.
2018-01-08 Dmitry V. Levin <ldv@altlinux.org>
* sysdeps/unix/sysv/linux/tst-ttyname.c (do_in_chroot_1): Skip the

4
sysdeps/ia64/memchr.S
View File

@ -67,6 +67,10 @@ ENTRY(__memchr)
.body
mov ret0 = str
add last = str, in2 // last byte
;;
cmp.ltu p6, p0 = last, str
;;
(p6) mov last = -1
and tmp = 7, str // tmp = str % 8
cmp.ne p7, p0 = r0, r0 // clear p7
extr.u chr = in1, 0, 8 // chr = (unsigned char) in1