From 6d055c058dc6880f75a1936efa5bea3c49216119 Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Sun, 28 Apr 2019 13:21:50 +0200 Subject: [PATCH] libdwfl: Don't call realloc with zero in cu.c addraranges. Calling realloc when naranges is zero will result is trying to free aranges. If realloc does free aranges it returns NULL, which means aranges is still assigned. This is likely not a problem, because in most cases aranges will be NULL already. But if it was not and naranges does turn out to be zero after reduction (which would be invalid DWARF) we are left with a dangling pointer. Signed-off-by: Mark Wielaard --- libdwfl/ChangeLog | 4 ++++ libdwfl/cu.c | 7 +++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index 1da888f..3e19d9b 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,7 @@ +2019-04-28 Mark Wielaard + + * cu.c (addrarange): Only call realloc when naranges is not zero. + 2019-03-27 Mark Wielaard * dwfl_segment_report_module.c (dwfl_segment_report_module): Check diff --git a/libdwfl/cu.c b/libdwfl/cu.c index 94bfad8..4de6624 100644 --- a/libdwfl/cu.c +++ b/libdwfl/cu.c @@ -83,8 +83,11 @@ addrarange (Dwfl_Module *mod, Dwarf_Addr addr, struct dwfl_arange **arange) /* Store the final array, which is probably much smaller than before. */ mod->naranges = naranges; - mod->aranges = (realloc (aranges, naranges * sizeof aranges[0]) - ?: aranges); + if (naranges > 0) + mod->aranges = (realloc (aranges, naranges * sizeof aranges[0]) + ?: aranges); + else if (aranges != NULL) + free (aranges); mod->lazycu += naranges; } -- 2.7.4