From df33285b60290fadefd140ee2fe616f750105d2f Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Thu, 29 Aug 2019 17:46:52 +0200 Subject: [PATCH] nm: Fix latent memory leak in show_symbols. If there are just a handful of symbols then memory for them is allocated on the stack, otherwise the memory is malloced. So before freeing the memory we need to check the number of entries to know if the memory was heap allocated or not. But since not all entries might be used we might have decreased the number of entries to the number we will actually show. Remember the original symbol entries to not have a memory leak. Signed-off-by: Mark Wielaard --- src/ChangeLog | 5 +++++ src/nm.c | 3 ++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/src/ChangeLog b/src/ChangeLog index aeb62328..cb64f7d9 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,8 @@ +2019-08-26 Mark Wielaard + + * nm.c (show_symbols): Remember nentries_orig and check before + freeing sym_mem. + 2019-07-05 Omar Sandoval * Makefile.am: Remove -ldl. diff --git a/src/nm.c b/src/nm.c index da1350b4..7f6cf2a2 100644 --- a/src/nm.c +++ b/src/nm.c @@ -1438,6 +1438,7 @@ show_symbols (int fd, Ebl *ebl, GElf_Ehdr *ehdr, free (demangle_buffer); #endif /* Now we know the exact number. */ + size_t nentries_orig = nentries; nentries = nentries_used; /* Sort the entries according to the users wishes. */ @@ -1472,7 +1473,7 @@ show_symbols (int fd, Ebl *ebl, GElf_Ehdr *ehdr, } /* Free all memory. */ - if (nentries * sizeof (sym_mem[0]) >= MAX_STACK_ALLOC) + if (nentries_orig * sizeof (sym_mem[0]) >= MAX_STACK_ALLOC) free (sym_mem); obstack_free (&whereob, NULL); -- 2.20.1