https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88890
Bug ID: 88890
Summary: libbacktrace on 32-bit system with _FILE_OFFSET_BITS
== 64
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libbacktrace
Assignee: unassigned at gcc dot gnu.org
Reporter: vries at gcc dot gnu.org
CC: ian at gcc dot gnu.org
Target Milestone: ---
In libbacktrace we use views to load portions of files into memory:
...
extern int backtrace_get_view (struct backtrace_state *state, int descriptor,
off_t offset, size_t size,
backtrace_error_callback error_callback,
void *data, struct backtrace_view *view);
...
One example using this function is:
...
off_t min_offset;
off_t max_offset;
...
/* Read all the debug sections in a single view, since they are
probably adjacent in the file. We never release this view. */
min_offset = 0;
max_offset = 0;
for (i = 0; i < (int) DEBUG_MAX; ++i)
{
off_t end;
if (sections[i].size == 0)
continue;
if (min_offset == 0 || sections[i].offset < min_offset)
min_offset = sections[i].offset;
end = sections[i].offset + sections[i].size;
if (end > max_offset)
max_offset = end;
}
if (min_offset == 0 || max_offset == 0)
{
if (!backtrace_close (descriptor, error_callback, data))
goto fail;
return 1;
}
if (!backtrace_get_view (state, descriptor, min_offset,
max_offset - min_offset,
error_callback, data, &debug_view))
goto fail;
debug_view_valid = 1;
...
In the case of a 32-bit system with _FILE_OFFSET_BITS == 64, well have size_t
32-bit unsigned and off_t 64-bit signed, so the max_offset - min_offset
argument for the size parameter may be bigger than the size_t type of the size
parameter allows.
ISTM that the easiest way to fix this, is to change the type of the size
parameter to off_t, and to figure out in the implementation of
backtrace_get_view whether the value of size fits in size_t, and if not, return
with failure.
