Hi Frank,
could you sent a patch including your good description with your
Signed-Off-By? For example with git format-patch -s origin
Thanks in advance
Waldemar
Frank Mehnert wrote,
Hi,
static analysis tools complain that the following code lacks a null-pointer
check:
ldso/ldso/dl-elf.c:
/*
* Add this object into the symbol chain
*/
if (*rpnt
#ifdef __LDSO_STANDALONE_SUPPORT__
/* Do not create a new chain entry for the main executable */
&& (*rpnt)->dyn
#endif
) {
(*rpnt)->next = _dl_malloc(sizeof(struct dyn_elf));
_dl_memset((*rpnt)->next, 0, sizeof(struct dyn_elf));
(*rpnt)->next->prev = (*rpnt);
*rpnt = (*rpnt)->next;
}
#ifndef SHARED
/* When statically linked, the first time we dlopen a DSO
* the *rpnt is NULL, so we need to allocate memory for it,
* and initialize the _dl_symbol_table.
*/
else {
*rpnt = _dl_symbol_tables = _dl_malloc(sizeof(struct dyn_elf));
_dl_memset(*rpnt, 0, sizeof(struct dyn_elf));
}
#endif
(*rpnt)->dyn = tpnt;
^^^^^^^^^^^^^^^^^^^^
There is a check for (*rpnt == NULL) right after the first comment but the
"else" case which performs an allocation does only exist if SHARED is not
defined. Otherwise it may happen (at least in theory) that *rpnt=NULL when
executing
(*rpnt)->dyn = tpnt;
Proposed fix:
diff --git a/ldso/ldso/dl-elf.c b/ldso/ldso/dl-elf.c
index 8210a012e..3ba3144e2 100644
--- a/ldso/ldso/dl-elf.c
+++ b/ldso/ldso/dl-elf.c
@@ -900,7 +900,8 @@ struct elf_resolve *_dl_load_elf_shared_library(unsigned int rflags,
_dl_memset(*rpnt, 0, sizeof(struct dyn_elf));
}
#endif
- (*rpnt)->dyn = tpnt;
+ if (*rpnt)
+ (*rpnt)->dyn = tpnt;
tpnt->usage_count++;
if (tpnt->rtld_flags & RTLD_NODELETE)
tpnt->usage_count++;
Kind regards
Frank
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