lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20191026131910.3435-57-sashal@kernel.org>
Date:   Sat, 26 Oct 2019 09:19:08 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Joel Colledge <joel.colledge@...bit.com>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        Kieran Bingham <kbingham@...nel.org>,
        Leonard Crestez <leonard.crestez@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 57/59] scripts/gdb: fix lx-dmesg when CONFIG_PRINTK_CALLER is set

From: Joel Colledge <joel.colledge@...bit.com>

[ Upstream commit ca210ba32ef7537b02731bfe255ed8eb1e4e2b59 ]

When CONFIG_PRINTK_CALLER is set, struct printk_log contains an
additional member caller_id.  This affects the offset of the log text.
Account for this by using the type information from gdb to determine all
the offsets instead of using hardcoded values.

This fixes following error:

  (gdb) lx-dmesg
  Python Exception <class 'ValueError'> embedded null character:
  Error occurred in Python command: embedded null character

The read_u* utility functions now take an offset argument to make them
easier to use.

Link: http://lkml.kernel.org/r/20191011142500.2339-1-joel.colledge@linbit.com
Signed-off-by: Joel Colledge <joel.colledge@...bit.com>
Reviewed-by: Jan Kiszka <jan.kiszka@...mens.com>
Cc: Kieran Bingham <kbingham@...nel.org>
Cc: Leonard Crestez <leonard.crestez@....com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 scripts/gdb/linux/dmesg.py | 16 ++++++++++++----
 scripts/gdb/linux/utils.py | 25 +++++++++++++------------
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py
index 6d2e09a2ad2f9..2fa7bb83885f0 100644
--- a/scripts/gdb/linux/dmesg.py
+++ b/scripts/gdb/linux/dmesg.py
@@ -16,6 +16,8 @@ import sys
 
 from linux import utils
 
+printk_log_type = utils.CachedType("struct printk_log")
+
 
 class LxDmesg(gdb.Command):
     """Print Linux kernel log buffer."""
@@ -42,9 +44,14 @@ class LxDmesg(gdb.Command):
             b = utils.read_memoryview(inf, log_buf_addr, log_next_idx)
             log_buf = a.tobytes() + b.tobytes()
 
+        length_offset = printk_log_type.get_type()['len'].bitpos // 8
+        text_len_offset = printk_log_type.get_type()['text_len'].bitpos // 8
+        time_stamp_offset = printk_log_type.get_type()['ts_nsec'].bitpos // 8
+        text_offset = printk_log_type.get_type().sizeof
+
         pos = 0
         while pos < log_buf.__len__():
-            length = utils.read_u16(log_buf[pos + 8:pos + 10])
+            length = utils.read_u16(log_buf, pos + length_offset)
             if length == 0:
                 if log_buf_2nd_half == -1:
                     gdb.write("Corrupted log buffer!\n")
@@ -52,10 +59,11 @@ class LxDmesg(gdb.Command):
                 pos = log_buf_2nd_half
                 continue
 
-            text_len = utils.read_u16(log_buf[pos + 10:pos + 12])
-            text = log_buf[pos + 16:pos + 16 + text_len].decode(
+            text_len = utils.read_u16(log_buf, pos + text_len_offset)
+            text_start = pos + text_offset
+            text = log_buf[text_start:text_start + text_len].decode(
                 encoding='utf8', errors='replace')
-            time_stamp = utils.read_u64(log_buf[pos:pos + 8])
+            time_stamp = utils.read_u64(log_buf, pos + time_stamp_offset)
 
             for line in text.splitlines():
                 msg = u"[{time:12.6f}] {line}\n".format(
diff --git a/scripts/gdb/linux/utils.py b/scripts/gdb/linux/utils.py
index 50805874cfc38..802acfee6785a 100644
--- a/scripts/gdb/linux/utils.py
+++ b/scripts/gdb/linux/utils.py
@@ -91,15 +91,16 @@ def read_memoryview(inf, start, length):
     return memoryview(inf.read_memory(start, length))
 
 
-def read_u16(buffer):
+def read_u16(buffer, offset):
+    buffer_val = buffer[offset:offset + 2]
     value = [0, 0]
 
-    if type(buffer[0]) is str:
-        value[0] = ord(buffer[0])
-        value[1] = ord(buffer[1])
+    if type(buffer_val[0]) is str:
+        value[0] = ord(buffer_val[0])
+        value[1] = ord(buffer_val[1])
     else:
-        value[0] = buffer[0]
-        value[1] = buffer[1]
+        value[0] = buffer_val[0]
+        value[1] = buffer_val[1]
 
     if get_target_endianness() == LITTLE_ENDIAN:
         return value[0] + (value[1] << 8)
@@ -107,18 +108,18 @@ def read_u16(buffer):
         return value[1] + (value[0] << 8)
 
 
-def read_u32(buffer):
+def read_u32(buffer, offset):
     if get_target_endianness() == LITTLE_ENDIAN:
-        return read_u16(buffer[0:2]) + (read_u16(buffer[2:4]) << 16)
+        return read_u16(buffer, offset) + (read_u16(buffer, offset + 2) << 16)
     else:
-        return read_u16(buffer[2:4]) + (read_u16(buffer[0:2]) << 16)
+        return read_u16(buffer, offset + 2) + (read_u16(buffer, offset) << 16)
 
 
-def read_u64(buffer):
+def read_u64(buffer, offset):
     if get_target_endianness() == LITTLE_ENDIAN:
-        return read_u32(buffer[0:4]) + (read_u32(buffer[4:8]) << 32)
+        return read_u32(buffer, offset) + (read_u32(buffer, offset + 4) << 32)
     else:
-        return read_u32(buffer[4:8]) + (read_u32(buffer[0:4]) << 32)
+        return read_u32(buffer, offset + 4) + (read_u32(buffer, offset) << 32)
 
 
 target_arch = None
-- 
2.20.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ