From 23ddab8569ef8ae3488c1d67b6bccaa081c73245 Mon Sep 17 00:00:00 2001 From: "Dmitry V. Levin" Date: Fri, 12 Jan 2018 18:12:24 +0300 Subject: [PATCH] make getcwd fail if it cannot obtain an absolute path Currently getcwd(3) can succeed without returning an absolute path because the underlying getcwd syscall, starting with linux commit v2.6.36-rc1~96^2~2, may succeed without returning an absolute path. This is a conformance issue because "The getcwd() function shall place an absolute pathname of the current working directory in the array pointed to by buf, and return buf". Fix this by checking the path returned by syscall and failing with ENOENT if the path is not absolute. The error code is chosen for consistency with the case when the current directory is unlinked. Similar issue was fixed in glibc recently, see https://sourceware.org/bugzilla/show_bug.cgi?id=22679 --- src/unistd/getcwd.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/src/unistd/getcwd.c b/src/unistd/getcwd.c index a7b925d2..103fbbb5 100644 --- a/src/unistd/getcwd.c +++ b/src/unistd/getcwd.c @@ -14,6 +14,12 @@ char *getcwd(char *buf, size_t size) errno = EINVAL; return 0; } - if (syscall(SYS_getcwd, buf, size) < 0) return 0; + long ret = syscall(SYS_getcwd, buf, size); + if (ret < 0) + return 0; + if (ret == 0 || buf[0] != '/') { + errno = ENOENT; + return 0; + } return buf == tmp ? strdup(buf) : buf; }