From b6838b520afa8346751577cd7ccbe0b906cd3a52 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 30 Sep 2016 11:33:47 +0200 Subject: ash: [VAR] Sanitise environment variable names on entry Upstream commit: Date: Sat, 25 Feb 2012 15:35:18 +0800 [VAR] Sanitise environment variable names on entry On Tue, Feb 14, 2012 at 10:48:48AM +0000, harald@redhat.com wrote: > "export -p" prints all environment variables, without checking if the > environment variable is a valid dash variable name. > > IMHO, the only valid usecase for "export -p" is to eval the output. > > $ eval $(export -p); echo OK > OK > > Without this patch the following test does error out with: > > test.py: > import os > os.environ["test-test"]="test" > os.environ["test_test"]="test" > os.execv("./dash", [ './dash', '-c', 'eval $(export -p); echo OK' ]) > > $ python test.py > ./dash: 1: export: test-test: bad variable name > > Of course the results can be more evil, if the environment variable > name is crafted, that it injects valid shell code. This patch fixes the issue by sanitising all environment variable names upon entry into the shell. Signed-off-by: Herbert Xu Signed-off-by: Denys Vlasenko --- shell/ash.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'shell') diff --git a/shell/ash.c b/shell/ash.c index db943f6c7..59905aa7b 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -13119,7 +13119,8 @@ init(void) initvar(); for (envp = environ; envp && *envp; envp++) { - if (strchr(*envp, '=')) { + p = endofname(*envp); + if (p != *envp && *p == '=') { setvareq(*envp, VEXPORT|VTEXTFIXED); } } -- cgit v1.2.3