From c1f46f9db723d88082899ee703aa00779230d510 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 3 Feb 2021 14:19:27 -0300 Subject: pthread: Remove alloca usage from __sem_check_add_mapping sem_open already returns EINVAL for input names larger than NAME_MAX, so it can assume the largest name length with tfind. Checked on x86_64-linux-gnu. --- sysdeps/pthread/sem_routines.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/sysdeps/pthread/sem_routines.c b/sysdeps/pthread/sem_routines.c index 78d9364ebd..ea7a445324 100644 --- a/sysdeps/pthread/sem_routines.c +++ b/sysdeps/pthread/sem_routines.c @@ -31,6 +31,15 @@ struct inuse_sem char name[]; }; +struct search_sem +{ + dev_t dev; + ino_t ino; + int refcnt; + sem_t *sem; + char name[NAME_MAX]; +}; + /* Comparison function for search of existing mapping. */ static int sem_search (const void *a, const void *b) @@ -61,6 +70,9 @@ sem_t * __sem_check_add_mapping (const char *name, int fd, sem_t *existing) { size_t namelen = strlen (name); + if (namelen > NAME_MAX) + return SEM_FAILED; + sem_t *result = SEM_FAILED; /* Get the information about the file. */ @@ -71,13 +83,12 @@ __sem_check_add_mapping (const char *name, int fd, sem_t *existing) lll_lock (sem_mappings_lock, LLL_PRIVATE); /* Search for an existing mapping given the information we have. */ - struct inuse_sem *fake; - fake = (struct inuse_sem *) alloca (sizeof (*fake) + namelen); - memcpy (fake->name, name, namelen); - fake->dev = st.st_dev; - fake->ino = st.st_ino; + struct search_sem fake; + memcpy (fake.name, name, namelen); + fake.dev = st.st_dev; + fake.ino = st.st_ino; - struct inuse_sem **foundp = __tfind (fake, &sem_mappings, sem_search); + struct inuse_sem **foundp = __tfind (&fake, &sem_mappings, sem_search); if (foundp != NULL) { /* There is already a mapping. Use it. */ -- cgit 1.4.1