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fix CVE-2021-3999

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(cherry picked from commit 29565817f88a630643f174796bc9f66b4643ca1f)
This commit is contained in:
liqingqing_1229 2022-01-24 17:12:43 +08:00 committed by openeuler-sync-bot
parent 9ddfe3685f
commit 8941dd2d50
2 changed files with 77 additions and 3 deletions
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70
getcwd-Set-errno-to-ERANGE-for-size-1-CVE-2021-3999.patch Normal file
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@ -0,0 +1,70 @@
From 472e799a5f2102bc0c3206dbd5a801765fceb39c Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date: Fri, 21 Jan 2022 23:32:56 +0530
Subject: [PATCH] getcwd: Set errno to ERANGE for size == 1 (CVE-2021-3999)
No valid path returned by getcwd would fit into 1 byte, so reject the
size early and return NULL with errno set to ERANGE. This change is
prompted by CVE-2021-3999, which describes a single byte buffer
underflow and overflow when all of the following conditions are met:
- The buffer size (i.e. the second argument of getcwd) is 1 byte
- The current working directory is too long
- '/' is also mounted on the current working directory
Sequence of events:
- In sysdeps/unix/sysv/linux/getcwd.c, the syscall returns ENAMETOOLONG
because the linux kernel checks for name length before it checks
buffer size
- The code falls back to the generic getcwd in sysdeps/posix
- In the generic func, the buf[0] is set to '\0' on line 269
- this while loop on line 282 is bypassed:
while (!(thisdev == rootdev && thisino == rootino))
since the rootfs (/) is bind mounted onto the directory and the flow
goes on to line 492, where it puts a '/' in the byte before the
buffer.
- Finally on line 500, it moves 2 bytes (the underflowed byte and the
'\0') to the buf[0] and buf[1], resulting in a 1 byte buffer overflow.
- buf is returned on line 514 and errno is not set.
This resolves BZ #28769.
Reviewed-by: Andreas Schwab <schwab@linux-m68k.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Qualys Security Advisory <qsa@qualys.com>
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 23e0e8f5f1fb5ed150253d986ecccdc90c2dcd5e)
---
sysdeps/posix/getcwd.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/sysdeps/posix/getcwd.c b/sysdeps/posix/getcwd.c
index b53433a2..e3c1d77c 100644
--- a/sysdeps/posix/getcwd.c
+++ b/sysdeps/posix/getcwd.c
@@ -239,6 +239,14 @@ __getcwd (char *buf, size_t size)
int fd = AT_FDCWD;
char *path;
+
+ /* A size of 1 byte is never useful. */
+ if (size == 1)
+ {
+ __set_errno (ERANGE);
+ return NULL;
+ }
+
#ifndef NO_ALLOCATION
size_t allocated = size;
if (size == 0)
--
2.27.0

10
glibc.spec
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@ -59,7 +59,7 @@
##############################################################################
Name: glibc
Version: 2.28
Release: 86
Release: 87
Summary: The GNU libc libraries
License: %{all_license}
URL: http://www.gnu.org/software/glibc/
@ -148,6 +148,7 @@ Patch64: socket-Add-the-__sockaddr_un_set-function.patch
Patch65: CVE-2022-23219-Buffer-overflow-in-sunrpc-clnt_create.patch
Patch66: sunrpc-Test-case-for-clnt_create-unix-buffer-overflo.patch
Patch67: CVE-2022-23218-Buffer-overflow-in-sunrpc-svcunix_cre.patch
Patch68: getcwd-Set-errno-to-ERANGE-for-size-1-CVE-2021-3999.patch
Provides: ldconfig rtld(GNU_HASH) bundled(gnulib)
@ -1172,10 +1173,13 @@ fi
%doc hesiod/README.hesiod
%changelog
* Thu Jan 20 2021 Qingqing Li <liqingqing3@huawei.com> - 2.28-86
* Tue Jan 25 2022 Qingqing Li <liqingqing3@huawei.com> - 2.28-87
- fix CVE-2021-3999
* Thu Jan 20 2022 Qingqing Li <liqingqing3@huawei.com> - 2.28-86
- sunrpc: fix compile error
* Wed Jan 19 2021 Qingqing Li <liqingqing3@huawei.com> - 2.28-85
* Wed Jan 19 2022 Qingqing Li <liqingqing3@huawei.com> - 2.28-85
- sunrpc: fix CVE-2022-23218 and fix CVE-2022-23219
* Fri Dec 24 2021 Yang yanchao <yangyanchao6@huawei.com> - 2.28-84