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| author | Stefan Liebler <stli@linux.ibm.com> | 2021-06-29 11:37:28 +0200 |
|---|---|---|
| committer | Stefan Liebler <stli@linux.ibm.com> | 2021-07-01 16:46:59 +0200 |
| commit | 7c45df18e1c524775a88c1e6fc7eac0049b3de83 (patch) | |
| tree | 0dac930cc98dd8ecaffd9e11e2bf5d4130241ad8 | |
| parent | ba436665b1c9e8bcef76947a4b59706bc64ceead (diff) | |
| download | glibc-7c45df18e1c524775a88c1e6fc7eac0049b3de83.tar.gz glibc-7c45df18e1c524775a88c1e6fc7eac0049b3de83.tar.xz glibc-7c45df18e1c524775a88c1e6fc7eac0049b3de83.zip | |
s390: Fix MEMCHR_Z900_G5 ifunc-variant if n>=0x80000000 [BZ #28024]
On s390 (31bit), the pointer to the first byte after s always wraps around with n >= 0x80000000 and can lead to stop searching before end of s. Thus this patch just use NULL as byte after s in this case and the srst instruction stops searching with "not found" when wrapping around from top address to zero. This is observable with testcase string/test-memchr starting with commit "String: Add overflow tests for strnlen, memchr, and strncat [BZ #27974]" https://sourceware.org/git/?p=glibc.git;a=commit;h=da5a6fba0febbfc90896ce1b2eb75c6d8a88a72d
| -rw-r--r-- | sysdeps/s390/memchr-z900.S | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/sysdeps/s390/memchr-z900.S b/sysdeps/s390/memchr-z900.S index 90b8a32dd6..72fd9e023f 100644 --- a/sysdeps/s390/memchr-z900.S +++ b/sysdeps/s390/memchr-z900.S @@ -44,12 +44,25 @@ ENTRY(MEMCHR_Z900_G5) LGHI %r0,0xff NGR %r0,%r3 LGR %r1,%r2 +# if ! defined __s390x__ + tmlh %r4,32768 + jo 3f /* Jump away if n >= 0x80000000 */ +# endif la %r2,0(%r4,%r1) 0: srst %r2,%r1 jo 0b brc 13,1f SLGR %r2,%r2 1: br %r14 +# if ! defined __s390x__ + /* On s390 (31bit), the pointer to the first byte after s (stored in + r2) always wraps around with n >= 0x80000000 and can lead to stop + searching before end of s. Thus just use r2=0 in this case. + If r2 < r1, the srst instruction stops searching with cc=2 "not + found" when wrapping around from top address to zero. */ +3: SLGR %r2,%r2 + j 0b +# endif END(MEMCHR_Z900_G5) # if ! HAVE_MEMCHR_IFUNC |