commit 3eed6a6f0a400763313bc5dca6e3b22a75166dbe
author Érico Nogueira <ericonr@disroot.org> Sat Jul 10 00:24:59 2021 -0300
committer Rich Felker <dalias@aerifal.cx> Fri Aug 06 11:26:15 2021 -0400
tree 65c107bccdadc07a07db7fb4d8e7bd3b75f92774
parent 3f701faace7addc75d16dea8a6cd769fa5b3f260

fix error checking in pthread_getname_np

len is unsigned and can never be smaller than 0. though unlikely, an
error in read() would have lead to an out of bounds write to name.

Reported-by: Michael Forney <mforney@mforney.org>

src/thread/pthread_getname_np.c

diff --git a/src/thread/pthread_getname_np.c b/src/thread/pthread_getname_np.c
index 48d1a29..85504e4 100644
--- a/src/thread/pthread_getname_np.c
+++ b/src/thread/pthread_getname_np.c
@@ -17,7 +17,7 @@
 
 	snprintf(f, sizeof f, "/proc/self/task/%d/comm", thread->tid);
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
-	if ((fd = open(f, O_RDONLY|O_CLOEXEC)) < 0 || (len = read(fd, name, len)) < 0) status = errno;
+	if ((fd = open(f, O_RDONLY|O_CLOEXEC)) < 0 || (len = read(fd, name, len)) == -1) status = errno;
 	else name[len-1] = 0; /* remove trailing new line only if successful */
 	if (fd >= 0) close(fd);
 	pthread_setcancelstate(cs, 0);