diff options
| author | Dmitry V. Levin <ldv@altlinux.org> | 2020-06-02 21:00:51 +0300 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2020-06-17 23:05:05 +0200 |
| commit | b3583fca5fb654af2cfc1c08259abb9728272538 (patch) | |
| tree | ef9096a292898761281983a0755af0e06ad75349 /tools/lib/string.c | |
| parent | c920c545286270302d29fd63c05c3bd84828daee (diff) | |
s390: fix syscall_get_error for compat processes
If both the tracer and the tracee are compat processes, and gprs[2]
is assigned a value by __poke_user_compat, then the higher 32 bits
of gprs[2] are cleared, IS_ERR_VALUE() always returns false, and
syscall_get_error() always returns 0.
Fix the implementation by sign-extending the value for compat processes
the same way as x86 implementation does.
The bug was exposed to user space by commit 201766a20e30f ("ptrace: add
PTRACE_GET_SYSCALL_INFO request") and detected by strace test suite.
This change fixes strace syscall tampering on s390.
Link: https://lkml.kernel.org/r/20200602180051.GA2427@altlinux.org
Fixes: 753c4dd6a2fa2 ("[S390] ptrace changes")
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: stable@vger.kernel.org # v2.6.28+
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'tools/lib/string.c')
0 files changed, 0 insertions, 0 deletions