46 lines
1.7 KiB
Diff
46 lines
1.7 KiB
Diff
From 9a9da2c299a0adcd36b4efd1b1c0ee2883beba7b Mon Sep 17 00:00:00 2001
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From: Johnothan King <johnothanking@protonmail.com>
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Date: Mon, 6 Jul 2020 13:51:44 -0700
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Subject: [PATCH] Fix use of strdup on a NULL pointer (#63)
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The following set of commands can rarely cause a memory fault
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when auditing[*] is enabled, although most of the time it will
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simply cause ksh to write '(null)' to the auditing file in place
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of a tty name:
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$ [ -e /etc/ksh_audit ] || echo "/tmp/ksh_auditfile;$(id -u)" | sudo tee /etc/ksh_audit;
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$ v=$(ksh 2> /dev/null +o rc -ic $'getopts a:bc: opt --man\nprint $?')
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$ cat /tmp/ksh_auditfile
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1000;1593599493;(null); getopts a:bc: opt --man
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This happens because strdup is used unconditionally on the pointer
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returned by 'ttyname', which can be NULL if stderr is closed. This
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then causes 'hp->tty' to be set to null, as strdup returns NULL.
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See https://github.com/att/ast/issues/1028
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src/cmd/ksh93/edit/history.c:
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- Make strdup duplicate 'notty' instead of NULL to prevent
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crashes.
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[*] https://blog.fpmurphy.com/2008/12/ksh93-auditing-and-accounting.html
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Cherry-picked-by: Lukáš Zaoral <lzaoral@redhat.com>
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Upstream-commit: 9a9da2c299a0adcd36b4efd1b1c0ee2883beba7b
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---
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src/cmd/ksh93/edit/history.c | 2 +-
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1 files changed, 1 insertions(+), 1 deletions(-)
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diff --git a/src/cmd/ksh93/edit/history.c b/src/cmd/ksh93/edit/history.c
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index d6737e209ca0..f40f27b4a4d7 100644
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--- a/src/cmd/ksh93/edit/history.c
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+++ b/src/cmd/ksh93/edit/history.c
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@@ -395,7 +395,7 @@ int sh_histinit(void *sh_context)
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if(fd>=0)
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{
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fcntl(fd,F_SETFD,FD_CLOEXEC);
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- hp->tty = strdup(ttyname(2));
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+ hp->tty = strdup(isatty(2)?ttyname(2):"notty");
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hp->auditfp = sfnew((Sfio_t*)0,NULL,-1,fd,SF_WRITE);
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}
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}
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