89 lines
2.6 KiB
Diff
89 lines
2.6 KiB
Diff
From 0588bc446fd48bdb1965a6773d008c05a4ba16c1 Mon Sep 17 00:00:00 2001
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From: Alexander Graf <agraf@suse.de>
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Date: Sun, 20 Nov 2011 13:02:54 +0100
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Subject: [PATCH 02/37] linux-user: fix QEMU_STRACE=1 segfault
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While debugging some issues with QEMU_STRACE I stumbled over segmentation
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faults that were pretty reproducible. Turns out we tried to treat a
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normal return value as errno, resulting in an access over array boundaries
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for the resolution.
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Fix this by allowing failure to resolve invalid errnos into strings.
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Signed-off-by: Alexander Graf <agraf@suse.de>
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---
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v1 -> v2:
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- propagate fault further down, so we display the negative value
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v2 -> v3:
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- fix boolean logic
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- fix print_syscall_ret_addr
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---
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linux-user/strace.c | 18 ++++++++++++++----
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linux-user/syscall.c | 3 +++
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2 files changed, 17 insertions(+), 4 deletions(-)
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diff --git a/linux-user/strace.c b/linux-user/strace.c
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index 90027a1..269481e 100644
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--- a/linux-user/strace.c
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+++ b/linux-user/strace.c
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@@ -284,8 +284,13 @@ print_ipc(const struct syscallname *name,
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static void
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print_syscall_ret_addr(const struct syscallname *name, abi_long ret)
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{
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-if( ret == -1 ) {
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- gemu_log(" = -1 errno=%d (%s)\n", errno, target_strerror(errno));
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+ char *errstr = NULL;
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+
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+ if (ret == -1) {
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+ errstr = target_strerror(errno);
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+ }
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+ if ((ret == -1) && errstr) {
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+ gemu_log(" = -1 errno=%d (%s)\n", errno, errstr);
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} else {
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gemu_log(" = 0x" TARGET_ABI_FMT_lx "\n", ret);
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}
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@@ -1515,14 +1520,19 @@ void
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print_syscall_ret(int num, abi_long ret)
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{
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int i;
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+ char *errstr = NULL;
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for(i=0;i<nsyscalls;i++)
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if( scnames[i].nr == num ) {
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if( scnames[i].result != NULL ) {
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scnames[i].result(&scnames[i],ret);
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} else {
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- if( ret < 0 ) {
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- gemu_log(" = -1 errno=" TARGET_ABI_FMT_ld " (%s)\n", -ret, target_strerror(-ret));
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+ if (ret < 0) {
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+ errstr = target_strerror(-ret);
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+ }
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+ if (errstr) {
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+ gemu_log(" = -1 errno=" TARGET_ABI_FMT_ld " (%s)\n",
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+ -ret, errstr);
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} else {
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gemu_log(" = " TARGET_ABI_FMT_ld "\n", ret);
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}
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diff --git a/linux-user/syscall.c b/linux-user/syscall.c
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index f227097..f170724 100644
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--- a/linux-user/syscall.c
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+++ b/linux-user/syscall.c
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@@ -731,6 +731,9 @@ static inline int is_error(abi_long ret)
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char *target_strerror(int err)
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{
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+ if ((err >= ERRNO_TABLE_SIZE) || (err < 0)) {
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+ return NULL;
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+ }
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return strerror(target_to_host_errno(err));
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}
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--
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1.6.0.2
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