ksh/ksh-20120801-subshell-interrupt-segv.patch
Lukáš Zaoral 916efa1a46
fix crashes when interrupting subshells
Resolves: RHEL-11650
2024-01-26 15:25:04 +01:00

122 lines
4.4 KiB
Diff

From 70f6d758c0f2fda90bc3d49331397ffd62dca3af Mon Sep 17 00:00:00 2001
From: Martijn Dekker <martijn@inlv.org>
Date: Thu, 30 Jul 2020 01:22:11 +0100
Subject: [PATCH] Fix blocked signals after fork(2)ing external command in
subshell
When the classic fork/exec mechanism was used (via sh_fork()) to
run an external command from within a non-forking subshell, SIGINT
was blocked until that subshell was exited. If a subsequent loop
was run in the subshell, it became uninterruptible, e.g.:
$ arch/*/bin/ksh -c '(/usr/bin/true; while :; do :; done); exit'
^C^C^C^C^C
src/cmd/ksh93/sh/xec.c:
- sh_fork() did not reset the savesig variable in the parent part
of the fork when running in a virtual subshell. This had the
effect of delaying signal handling until exiting the subshell.
There is no reason for that subshell check that I can discern, so
this removes it.
I've verified that this causes no regression test failures
even when ksh is compiled with -DSHOPT_SPAWN=0 which means the
classic fork/exec mechanism is always used.
Fixes: https://github.com/ksh93/ksh/issues/86
Cherry-picked-by: Lukáš Zaoral <lzaoral@redhat.com>
Upstream-commit: 70f6d758c0f2fda90bc3d49331397ffd62dca3af
---
src/cmd/ksh93/sh/xec.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/src/cmd/ksh93/sh/xec.c b/src/cmd/ksh93/sh/xec.c
index a6ad50747548..baa8d6d1287a 100644
--- a/src/cmd/ksh93/sh/xec.c
+++ b/src/cmd/ksh93/sh/xec.c
@@ -2951,13 +2951,10 @@ pid_t sh_fork(Shell_t *shp,int flags, int *jobid)
shp->savesig = -1;
while(_sh_fork(shp,parent=fork(),flags,jobid) < 0);
sh_stats(STAT_FORKS);
- if(!shp->subshell)
- {
- sig = shp->savesig;
- shp->savesig = 0;
- if(sig>0)
- kill(getpid(),sig);
- }
+ sig = shp->savesig;
+ shp->savesig = 0;
+ if(sig>0)
+ kill(getpid(),sig);
job_fork(parent);
return(parent);
}
From 91a7c2e3e9feb8ac1391146ebcda9e6adfcd3cfb Mon Sep 17 00:00:00 2001
From: Martijn Dekker <martijn@inlv.org>
Date: Mon, 27 Dec 2021 03:00:15 +0000
Subject: [PATCH] Fix crash/freeze upon interrupting command substitution with
pipe
On some systems (at least Linux and macOS):
1. Run on a command line: t=$(sleep 10|while :; do :; done)
2. Press Ctrl+C in the first 10 seconds.
3. Execute any other command substitution. The shell crashes.
Analysis: Something in the job_wait() call in the sh_subshell()
restore routine may be interrupted by a signal such as SIGINT on
Linux and macOS. Exactly what that interruptible thing is remains
to be determined. In any case, since job_wait() was invoked after
sh_popcontext(), interrupting it caused the sh_subshell() restore
routine to be aborted, resulting in an inconsistent state of the
shell. The fix is to sh_popcontext() at a later stage instead.
src/cmd/ksh93/sh/subshell.c: sh_subshell():
- Move the sh_popcontext() call to near the end, just after
decreasing the subshell level counters and restoring the global
subshell data struct to its parent. This seems like a logical
place for it and could allow other things to be interrupted, too.
- Get rid of the if(shp->subshell) because it is known that the
value is > 0 at this point.
- The short exit routine run if the subshell forked now needs a new
sh_popcontext() call, because this is handled before restoring
the virtual subshell state.
Fixes: https://github.com/ksh93/ksh/issues/397
Cherry-picked-by: Lukáš Zaoral <lzaoral@redhat.com>
Upstream-commit: 91a7c2e3e9feb8ac1391146ebcda9e6adfcd3cfb
---
src/cmd/ksh93/sh/subshell.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/src/cmd/ksh93/sh/subshell.c b/src/cmd/ksh93/sh/subshell.c
@@ -681,10 +681,10 @@ Sfio_t *sh_subshell(Shell_t *shp,Shnode_t *t, volatile int flags, int comsub)
sh_trap(trap,0);
free(trap);
}
- sh_popcontext(shp,&buff);
if(shp->subshell==0) /* must be child process */
{
subshell_data = sp->prev;
+ sh_popcontext(shp,&buff);
if(jmpval==SH_JMPSCRIPT)
siglongjmp(*shp->jmplist,jmpval);
shp->exitval &= SH_EXITMASK;
@@ -886,10 +886,10 @@ Sfio_t *sh_subshell(Shell_t *shp,Shnode_t *t, volatile int flags, int comsub)
#if SHOPT_COSHELL
shp->coshell = sp->coshell;
#endif /* SHOPT_COSHELL */
- if(shp->subshell)
- SH_SUBSHELLNOD->nvalue.s = --shp->subshell;
+ SH_SUBSHELLNOD->nvalue.s = --shp->subshell;
subshell = shp->subshell;
subshell_data = sp->prev;
+ sh_popcontext(shp,&buff);
if(!argsav || argsav->dolrefcnt==argcnt)
sh_argfree(shp,argsav,0);
if(shp->topfd != buff.topfd)