linux

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Dmitry V. Levin b3583fca5f 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>

2020-06-17 23:05:05 +02:00

appldata

s390 updates for the 5.8 merge window

2020-06-08 12:05:31 -07:00

boot

mm: reorder includes after introduction of linux/pgtable.h

2020-06-09 09:39:13 -07:00

configs

s390 updates for the 5.7 merge window

2020-04-04 09:45:50 -07:00

crypto

s390/crypto: use scnprintf() instead of snprintf()