diff options
Diffstat (limited to 'main/musl/0052-ldso-avoid-spurious-possible-erroneous-work-for-libs.patch')
| -rw-r--r-- | main/musl/0052-ldso-avoid-spurious-possible-erroneous-work-for-libs.patch | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/main/musl/0052-ldso-avoid-spurious-possible-erroneous-work-for-libs.patch b/main/musl/0052-ldso-avoid-spurious-possible-erroneous-work-for-libs.patch new file mode 100644 index 0000000000..86ca7ea9e9 --- /dev/null +++ b/main/musl/0052-ldso-avoid-spurious-possible-erroneous-work-for-libs.patch @@ -0,0 +1,84 @@ +From 66b53cfa8876342f7e7d7907d30c719c38cd5a1b Mon Sep 17 00:00:00 2001 +From: Rich Felker <dalias@aerifal.cx> +Date: Tue, 4 Jul 2017 10:58:13 -0400 +Subject: [PATCH 52/52] ldso: avoid spurious & possible erroneous work for libs + with no deps + +a null pointer for a library's deps list was ambiguous: it could +indicate either no dependencies or that the dependency list had not +yet been populated. inability to distinguish could lead to spurious +work when dlopen is called multiple times on a library with no deps, +and due to related bugs, could actually cause other libraries to +falsely appear as dependencies, translating into false positives for +dlsym. + +avoid the problem by always initializing the deps pointer, pointing to +an empty list if there are no deps. rather than wasting memory and +introducing another failure path by allocating an empty list per +library, simply share a global dummy list. + +further fixes will be needed for related bugs, and much of this code +may end up being replaced. +--- + ldso/dynlink.c | 11 +++++++---- + 1 file changed, 7 insertions(+), 4 deletions(-) + +diff --git a/ldso/dynlink.c b/ldso/dynlink.c +index d20dbd87..239007ff 100644 +--- a/ldso/dynlink.c ++++ b/ldso/dynlink.c +@@ -129,6 +129,7 @@ static size_t static_tls_cnt; + static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE }; + static struct fdpic_loadmap *app_loadmap; + static struct fdpic_dummy_loadmap app_dummy_loadmap; ++static struct dso *const nodeps_dummy; + + struct debug *_dl_debug_addr = &debug; + +@@ -1125,6 +1126,7 @@ static void load_deps(struct dso *p) + } + } + } ++ if (!*deps) *deps = (struct dso **)&nodeps_dummy; + } + + static void load_preload(char *s) +@@ -1742,7 +1744,8 @@ void *dlopen(const char *file, int mode) + free(p->funcdescs); + if (p->rpath != p->rpath_orig) + free(p->rpath); +- free(p->deps); ++ if (p->deps != &nodeps_dummy) ++ free(p->deps); + unmap_library(p); + free(p); + } +@@ -1772,14 +1775,14 @@ void *dlopen(const char *file, int mode) + load_deps(p); + if (!p->relocated && (mode & RTLD_LAZY)) { + prepare_lazy(p); +- if (p->deps) for (i=0; p->deps[i]; i++) ++ for (i=0; p->deps[i]; i++) + if (!p->deps[i]->relocated) + prepare_lazy(p->deps[i]); + } + /* Make new symbols global, at least temporarily, so we can do + * relocations. If not RTLD_GLOBAL, this is reverted below. */ + add_syms(p); +- if (p->deps) for (i=0; p->deps[i]; i++) ++ for (i=0; p->deps[i]; i++) + add_syms(p->deps[i]); + reloc_all(p); + } +@@ -1878,7 +1881,7 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra) + return p->funcdescs + (sym - p->syms); + if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES)) + return laddr(p, sym->st_value); +- if (p->deps) for (i=0; p->deps[i]; i++) { ++ for (i=0; p->deps[i]; i++) { + if ((ght = p->deps[i]->ghashtab)) { + if (!gh) gh = gnu_hash(s); + sym = gnu_lookup(gh, ght, p->deps[i], s); +-- +2.13.1 + |