From 0a950dcf15bb9f7274c804dca490e9e20e475f3e Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Sat, 20 Aug 2016 21:04:31 +0200 Subject: [PATCH] verify that ttyname refers to the same file as the fd linux containers use separate mount namespace so the /proc symlink might not point to the right device if the fd was opened in the parent namespace, in this case return ENOENT. --- src/unistd/ttyname_r.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/src/unistd/ttyname_r.c b/src/unistd/ttyname_r.c index 8bac7b2f..a38ba4f2 100644 --- a/src/unistd/ttyname_r.c +++ b/src/unistd/ttyname_r.c @@ -1,10 +1,12 @@ #include #include +#include void __procfdname(char *, unsigned); int ttyname_r(int fd, char *name, size_t size) { + struct stat st1, st2; char procname[sizeof "/proc/self/fd/" + 3*sizeof(int) + 2]; ssize_t l; @@ -15,8 +17,13 @@ int ttyname_r(int fd, char *name, size_t size) if (l < 0) return errno; else if (l == size) return ERANGE; - else { - name[l] = 0; - return 0; - } + + name[l] = 0; + + if (stat(name, &st1) || fstat(fd, &st2)) + return errno; + if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino) + return ENOENT; + + return 0; } -- 2.25.1