diff options
| author | Mark Wielaard <mark@klomp.org> | 2021-12-12 23:26:18 +0100 |
|---|---|---|
| committer | Mark Wielaard <mark@klomp.org> | 2021-12-12 23:26:18 +0100 |
| commit | db862a11910a5d4c007c549c2b4ce4cad62f242b (patch) | |
| tree | 26617b35eddb02757146ed8ede413cc2e936eaba /libdwfl | |
| parent | 80ea3cf328eb94fd78e494d0128561f53e20114d (diff) | |
| download | elfutils-db862a11910a5d4c007c549c2b4ce4cad62f242b.tar.gz | |
libdwfl: Don't allocate more than SIZE_MAX in dwfl_segment_report_module.
The code in dwfl_segment_report_module tries to allocate and fill in
memory as described in a core file. Normally all memory in filled in
through the (phdrs) memory_callback or the read_eagerly callback. If
the last callback doesn't work we try to calloc file_trimmed_end bytes
and then try to fill in the parts of memory we can from the core file
at the correct offsets.
file_trimmed_end is a GElf_Off which is an unsigned 64bit type. On
32bit systems this means when cast to a size_t to do an allocation
might allocate truncated (much smaller) value. So make sure to not
allocate more than SIZE_MAX bytes.
It would be nice to have a better way to limit the amount of memory
allocated here. A core file might describe really big memory areas for
which it doesn't provide any data. In that case we really shouldn't
calloc mega- or giga-bytes of zeroed out memory.
Reported-by: Evgeny Vereshchagin <evvers@ya.ru>
Signed-off-by: Mark Wielaard <mark@klomp.org>
Diffstat (limited to 'libdwfl')
| -rw-r--r-- | libdwfl/ChangeLog | 5 | ||||
| -rw-r--r-- | libdwfl/dwfl_segment_report_module.c | 3 |
2 files changed, 8 insertions, 0 deletions
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index 856bd335..aaea164c 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,8 @@ +2021-12-12 Mark Wielaard <mark@klomp.org> + + * dwfl_segment_report_module.c (dwfl_segment_report_module): Don't + allocate more than SIZE_MAX. + 2021-12-09 Mark Wielaard <mark@klomp.org> * link_map.c (dwfl_link_map_report): Limit dyn_filesz malloc size diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c index f4acfe53..46564ec5 100644 --- a/libdwfl/dwfl_segment_report_module.c +++ b/libdwfl/dwfl_segment_report_module.c @@ -904,6 +904,9 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name, /* The caller wants to read the whole file in right now, but hasn't done it for us. Fill in a local image of the virtual file. */ + if (file_trimmed_end > SIZE_MAX) + goto out; + void *contents = calloc (1, file_trimmed_end); if (unlikely (contents == NULL)) goto out; |