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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