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[S390] Check for NULL termination in command line setup 

The current code in setup_boot_command_line() uses a heuristic to
detect an EBCDIC command line. It checks if any of the bytes in
the command line has bit one (0x80) set. In that case it is assumed
that we have an EBCDIC string and the complete command line is
converted.

On s390 there are cases where the boot loader provides a kernel
command line that is NULL terminated, but has random data after
the NULL termination. In that case, setup_boot_command_line()
might misinterpret an ASCII string for an EBCDIC string. A
subsequent string conversion can then damage the ASCII string.

This patch solves the problem by checking for NULL termination.
If no EBCDIC character has been found until the the NULL
termination has been found, we now assume that we have an ASCII
string.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Michael Holzheu 2011-12-27 11:25:46 +01:00 committed by Martin Schwidefsky
parent 272f01bf9b
commit 1fb810576f
1 changed files with 12 additions and 8 deletions
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20
arch/s390/kernel/early.c
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@ -434,18 +434,22 @@ static void __init append_to_cmdline(size_t (*ipl_data)(char *, size_t))
}
}
static void __init setup_boot_command_line(void)
static inline int has_ebcdic_char(const char *str)
{
int i;
/* convert arch command line to ascii */
for (i = 0; i < ARCH_COMMAND_LINE_SIZE; i++)
if (COMMAND_LINE[i] & 0x80)
break;
if (i < ARCH_COMMAND_LINE_SIZE)
EBCASC(COMMAND_LINE, ARCH_COMMAND_LINE_SIZE);
COMMAND_LINE[ARCH_COMMAND_LINE_SIZE-1] = 0;
for (i = 0; str[i]; i++)
if (str[i] & 0x80)
return 1;
return 0;
}
static void __init setup_boot_command_line(void)
{
COMMAND_LINE[ARCH_COMMAND_LINE_SIZE - 1] = 0;
/* convert arch command line to ascii if necessary */
if (has_ebcdic_char(COMMAND_LINE))
EBCASC(COMMAND_LINE, ARCH_COMMAND_LINE_SIZE);
/* copy arch command line */
strlcpy(boot_command_line, strstrip(COMMAND_LINE),
ARCH_COMMAND_LINE_SIZE);