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Resolves: RHEL-5685 - Fix crash on failure to trim ~/.sh_history

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Vincent Mihalkovic 2024-01-04 11:01:24 +01:00
parent 6a16730bcb
commit b1187a33ba
2 changed files with 108 additions and 0 deletions
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102
ksh-1.0.7-history-trim.patch Normal file
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@ -0,0 +1,102 @@
From 2075b2b96208ac8b989ca316dcdd674c3f488e2b Mon Sep 17 00:00:00 2001
From: Martijn Dekker <martijn@inlv.org>
Date: Thu, 28 Dec 2023 04:02:28 +0000
Subject: [PATCH] Subject: [PATCH] Fix crash on failure to trim ~/.sh_history
@vmihalko writes:
> We were able to reproduce an old issue mentioned in
> https://bugzilla.redhat.com/show_bug.cgi?id=1885399 using the
> latest version of ksh. The corresponding code has not changed
> much in the past few years.
>
> To provide further explanation, the problem arises when a user's
> .sh_history file grows to a size that triggers the hist_trim
> function, but the user lacks (after the creation of .sh_history)
> the necessary write permissions to their $HOME directory. As a
> result, ksh becomes stuck in a recursive loop between the
> sh_histinit(src/cmd/ksh93/edit/history.c#L203) function and the
> hist_trim(src/cmd/ksh93/edit/history.c#L417) function.
>
> Conditions for reproduction:
>
> 1. The size of the .sh_history file is larger than the HIST_MAX
> limit. (src/cmd/ksh93/edit/history.c, line 325)
> 2. .sh_history file has not been changed in the HIST_RECENT
> seconds (src/cmd/ksh93/edit/history.c, line 406)
> 3. The user does not have permission to write to the $HOME
> directory.
src/cmd/ksh93/edit/history.c: hist_trim():
- Print a warning and return if unlink(2) fails. The warning tells
the user to check the history file's parent directory is
writable. This is the best I realistically do for now, because
this function's basic method assumes a writable parent directory.
- The temp file fallback is deleted because it's fundamentally
flawed: it assumes the temp file is made on the same volume as
the history file and can simply be rename(2)'d in place. Even
on systems where this is the case, it doesn't appear to be
working correctly, but this is not worth looking into.
Resolves: https://github.com/ksh93/ksh/issues/695
---
src/cmd/ksh93/edit/history.c | 34 ++++------------------------------
1 file changed, 4 insertions(+), 30 deletions(-)
diff --git a/src/cmd/ksh93/edit/history.c b/src/cmd/ksh93/edit/history.c
index 1f6cd7c..0ed8e8a 100644
--- a/src/cmd/ksh93/edit/history.c
+++ b/src/cmd/ksh93/edit/history.c
@@ -461,34 +461,13 @@ static History_t* hist_trim(History_t *hp, int n)
register char *cp;
register int incmd=1, c=0;
register History_t *hist_new, *hist_old = hp;
- char *buff, *endbuff, *tmpname=0;
+ char *buff, *endbuff;
off_t oldp,newp;
struct stat statb;
- unlink(hist_old->histname);
- if(access(hist_old->histname,F_OK) >= 0)
+ if(unlink(hist_old->histname) < 0)
{
- /* The unlink can fail on windows 95 */
- int fd;
- char *last, *name=hist_old->histname;
- close(sffileno(hist_old->histfp));
- tmpname = (char*)malloc(strlen(name)+14);
- if(last = strrchr(name,'/'))
- {
- *last = 0;
- pathtmp(tmpname,name,"hist",NIL(int*));
- *last = '/';
- }
- else
- pathtmp(tmpname,".","hist",NIL(int*));
- if(rename(name,tmpname) < 0)
- {
- free(tmpname);
- tmpname = name;
- }
- fd = open(tmpname,O_RDONLY);
- sfsetfd(hist_old->histfp,fd);
- if(tmpname==name)
- tmpname = 0;
+ errormsg(SH_DICT,ERROR_warn(0),"cannot trim history file %s; make sure parent directory is writable",hist_old->histname);
+ return hist_ptr = hist_old;
}
hist_ptr = 0;
if(fstat(sffileno(hist_old->histfp),&statb)>=0)
@@ -543,11 +522,6 @@ static History_t* hist_trim(History_t *hp, int n)
}
hist_cancel(hist_new);
sfclose(hist_old->histfp);
- if(tmpname)
- {
- unlink(tmpname);
- free(tmpname);
- }
free((char*)hist_old);
return hist_ptr = hist_new;
}
--
2.42.0

6
ksh.spec
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@ -249,6 +249,9 @@ Patch97: ksh-20120801-segfault-cd-paths.patch
# upstream commit: https://github.com/ksh93/ksh/commit/f9d28935bb93fe7336ba8c5eab4231050de2e11e
Patch98: ksh-20120801-xtrace-utf8-quoting.patch
#https://github.com/ksh93/ksh/commit/2075b2b96208ac8b989ca316dcdd674c3f488e2b
Patch99: %{name}-1.0.7-history-trim.patch
Conflicts: pdksh
Requires: coreutils, diffutils, chkconfig
BuildRequires: bison
@ -402,6 +405,9 @@ fi
%config(noreplace) %{_sysconfdir}/binfmt.d/kshcomp.conf
%changelog
* Wed Jan 03 2024 Vincent Mihalkovic <vmihalko@redhat.com> - 20120801-265
- Fix crash on failure to trim ~/.sh_history (#5685)
* Wed Nov 22 2023 Vincent Mihalkovic <vmihalko@redhat.com> - 20120801-264
- Remove broken monitor patch