!4 【轻量级 PR】：check sanity of SC_ARG_MAX

From: @chenmingmin
Reviewed-by: @SuperSix173
Signed-off-by: @SuperSix173

backport-pgrep-check-sanity-of-SC_ARG_MAX.patch

@@ -0,0 +1,60 @@
+From bb96fc42956c9ed926a1b958ab715f8b4a663dec Mon Sep 17 00:00:00 2001
+From: Craig Small <csmall@dropbear.xyz>
+Date: Sun, 5 Jan 2020 15:05:55 +1100
+Subject: [PATCH] pgrep: check sanity of SC_ARG_MAX
+
+A kernel change means we cannot trust what sysconf(SC_ARG_MAX)
+returns. We clamp it so its more than 4096 and less than 128*1024
+which is what findutils does.
+
+References:
+ procps-ng/procps#152
+ https://git.savannah.gnu.org/cgit/findutils.git/tree/lib/buildcmd.c#n535
+ https://lwn.net/Articles/727862/
+---
+ pgrep.c | 22 +++++++++++++++++++++-
+ 1 file changed, 21 insertions(+), 1 deletion(-)
+
+diff --git a/pgrep.c b/pgrep.c
+index 01563db..bde7448 100644
+--- a/pgrep.c
++++ b/pgrep.c
+@@ -485,6 +485,26 @@ static regex_t * do_regcomp (void)
+ 	return preg;
+ }
+ 
++/*
++ * SC_ARG_MAX used to return the maximum size a command line can be
++ * however changes to the kernel mean this can be bigger than we can
++ * alloc. Clamp it to 128kB like xargs and friends do
++ * Should also not be smaller than POSIX_ARG_MAX which is 4096
++ */
++static size_t get_arg_max(void)
++{
++#define MIN_ARG_SIZE 4096u
++#define MAX_ARG_SIZE (128u * 1024u)
++
++    size_t val = sysconf(_SC_ARG_MAX);
++
++    if (val < MIN_ARG_SIZE)
++	val = MIN_ARG_SIZE;
++    if (val > MAX_ARG_SIZE)
++	val = MAX_ARG_SIZE;
++
++    return val;
++}
+ static struct el * select_procs (int *num)
+ {
+ 	PROCTAB *ptp;
+@@ -497,7 +517,7 @@ static struct el * select_procs (int *num)
+ 	regex_t *preg;
+ 	pid_t myself = getpid();
+ 	struct el *list = NULL;
+-        long cmdlen = sysconf(_SC_ARG_MAX) * sizeof(char);
++        long cmdlen = get_arg_max() * sizeof(char);
+ 	char *cmdline = xmalloc(cmdlen);
+ 	char *cmdsearch = xmalloc(cmdlen);
+ 	char *cmdoutput = xmalloc(cmdlen);
+-- 
+2.22.0.windows.1
+

procps-ng.spec

@@ -1,6 +1,6 @@
 Name: 		procps-ng
 Version: 	3.3.16
-Release:    11
+Release:    12
 Summary: 	Utilities that provide system information.
 License: 	GPL+ and GPLv2 and GPLv2+ and GPLv3+ and LGPLv2+
 URL: 		https://sourceforge.net/projects/procps-ng/
@@ -11,6 +11,7 @@ Source2: 	README.top
 
 Patch9000: 	feature-add-options-M-and-N-for-top.patch
 Patch9001: 	bugfix-top-exit-with-error-when-pid-overflow.patch
+Patch9002: 	backport-pgrep-check-sanity-of-SC_ARG_MAX.patch
 
 BuildRequires: 	ncurses-devel libtool autoconf automake gcc gettext-devel systemd-devel
 
@@ -93,6 +94,14 @@ ln -s %{_bindir}/pidof %{buildroot}%{_sbindir}/pidof
 %{_mandir}/translated
 
 %changelog
+* Wed Sep 23 2020 MarsChan <chenmingmin@huawei.com> - 3.3.16-12
+- Type:bugfix
+- ID:NA
+- SUG:restart
+- DESC:A kernel change means we cannot trust what sysconf(SC_ARG_MAX)
+       returns. We clamp it so its more than 4096 and less than 128*1024
+       which is what findutils does.
+
 * Tue Jan 7 2020 MarsChan <chenmingmin@huawei.com> - 3.3.16-11
 - Type:upgrade
 - ID:NA