It was reported that trace_printk() was not reporting properly

values that came after a dereference pointer.
 
 trace_printk() utilizes vbin_printf() and bstr_printf() to keep the
 overhead of tracing down. vbin_printf() does not do any conversions
 and just stors the string format and the raw arguments into the
 buffer. bstr_printf() is used to read the buffer and does the conversions
 to complete the printf() output.
 
 This can be troublesome with dereferenced pointers because the reference
 may be different from the time vbin_printf() is called to the time
 bstr_printf() is called. To fix this, a prior commit changed vbin_printf()
 to convert dereferenced pointers into strings and load the converted
 string into the buffer. But the change to bstr_printf() had an off-by-one
 error and didn't account for the nul character at the end of the string
 and this corrupted the rest of the values in the format that came after
 a dereferenced pointer.
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 b29kbWlzLm9yZwAKCRAp5XQQmuv6qnraAQDVbp0aWOpS73YUVbW/bArC8t8Z6/9h
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Merge tag 'trace-v4.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Steven writes:
  "vsprint fix:

   It was reported that trace_printk() was not reporting properly
   values that came after a dereference pointer.

   trace_printk() utilizes vbin_printf() and bstr_printf() to keep the
   overhead of tracing down. vbin_printf() does not do any conversions
   and just stors the string format and the raw arguments into the
   buffer. bstr_printf() is used to read the buffer and does the
   conversions to complete the printf() output.

   This can be troublesome with dereferenced pointers because the
   reference may be different from the time vbin_printf() is called to
   the time bstr_printf() is called. To fix this, a prior commit changed
   vbin_printf() to convert dereferenced pointers into strings and load
   the converted string into the buffer. But the change to bstr_printf()
   had an off-by-one error and didn't account for the nul character at
   the end of the string and this corrupted the rest of the values in
   the format that came after a dereferenced pointer."

* tag 'trace-v4.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  vsprintf: Fix off-by-one bug in bstr_printf() processing dereferenced pointers
This commit is contained in:
Greg Kroah-Hartman 2018-10-10 22:09:44 +02:00
commit 588b593821

View file

@ -2794,7 +2794,7 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
copy = end - str;
memcpy(str, args, copy);
str += len;
args += len;
args += len + 1;
}
}
if (process)