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[PATCH] libdwfl: Don't assume auxv or r_debug data is properly aligned in link_map.
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Sun, 31 May 2015 21:26:04 +0200
- Subject: [PATCH] libdwfl: Don't assume auxv or r_debug data is properly aligned in link_map.
core file data isn't guaranteed to be alligned properly. Use
read_(4|8)ubyte_unaligned_noncvt to read values, types and addresses.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
libdwfl/ChangeLog | 7 +++++++
libdwfl/link_map.c | 25 +++++++++++++++----------
2 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index ffb34c0..f4e7484 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,5 +1,12 @@
2015-05-30 Mark Wielaard <mjw@redhat.com>
+ * link_map.c (check32): Use read_4ubyte_unaligned_noncvt to read
+ type and value.
+ (read_addrs): Use read_(4|8)ubyte_unaligned_noncvt or to read
+ adresses.
+
+2015-05-30 Mark Wielaard <mjw@redhat.com>
+
* find-debuginfo.c (dwfl_standard_find_debuginfo): Check file_name is
not NULL before calling canonicalize_file_name.
diff --git a/libdwfl/link_map.c b/libdwfl/link_map.c
index a5a6968..030c600 100644
--- a/libdwfl/link_map.c
+++ b/libdwfl/link_map.c
@@ -58,8 +58,7 @@ auxv_format_probe (const void *auxv, size_t size,
inline bool check64 (size_t i)
{
/* The AUXV pointer might not even be naturally aligned for 64-bit
- data, because note payloads in a core file are not aligned.
- But we assume the data is 32-bit aligned. */
+ data, because note payloads in a core file are not aligned. */
uint64_t type = read_8ubyte_unaligned_noncvt (&u->a64[i].a_type);
uint64_t val = read_8ubyte_unaligned_noncvt (&u->a64[i].a_un.a_val);
@@ -83,15 +82,21 @@ auxv_format_probe (const void *auxv, size_t size,
inline bool check32 (size_t i)
{
- if (u->a32[i].a_type == BE32 (PROBE_TYPE)
- && u->a32[i].a_un.a_val == BE32 (PROBE_VAL32))
+ /* The AUXV pointer might not even be naturally aligned for 32-bit
+ data, because note payloads in a core file are not aligned. */
+
+ uint32_t type = read_4ubyte_unaligned_noncvt (&u->a32[i].a_type);
+ uint32_t val = read_4ubyte_unaligned_noncvt (&u->a32[i].a_un.a_val);
+
+ if (type == BE32 (PROBE_TYPE)
+ && val == BE32 (PROBE_VAL32))
{
*elfdata = ELFDATA2MSB;
return true;
}
- if (u->a32[i].a_type == LE32 (PROBE_TYPE)
- && u->a32[i].a_un.a_val == LE32 (PROBE_VAL32))
+ if (type == LE32 (PROBE_TYPE)
+ && val == LE32 (PROBE_VAL32))
{
*elfdata = ELFDATA2LSB;
return true;
@@ -285,19 +290,19 @@ report_r_debug (uint_fast8_t elfclass, uint_fast8_t elfdata,
{
if (elfdata == ELFDATA2MSB)
for (size_t i = 0; i < n; ++i)
- addrs[i] = BE32 (in->a32[i]);
+ addrs[i] = BE32 (read_4ubyte_unaligned_noncvt (&in->a32[i]));
else
for (size_t i = 0; i < n; ++i)
- addrs[i] = LE32 (in->a32[i]);
+ addrs[i] = LE32 (read_4ubyte_unaligned_noncvt (&in->a32[i]));
}
else
{
if (elfdata == ELFDATA2MSB)
for (size_t i = 0; i < n; ++i)
- addrs[i] = BE64 (in->a64[i]);
+ addrs[i] = BE64 (read_8ubyte_unaligned_noncvt (&in->a64[i]));
else
for (size_t i = 0; i < n; ++i)
- addrs[i] = LE64 (in->a64[i]);
+ addrs[i] = LE64 (read_8ubyte_unaligned_noncvt (&in->a64[i]));
}
return false;
--
2.4.2