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kmsg - properly print over-long continuation lines

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Reserve PREFIX_MAX bytes in the LOG_LINE_MAX line when buffering a
continuation line, to be able to properly prefix the LOG_LINE_MAX
line with the syslog prefix and timestamp when printing it.

Reported-By: Dave Jones <davej@redhat.com>
Signed-off-by: Kay Sievers <kay@vrfy.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kay Sievers 2012-07-16 18:35:29 -07:00 committed by Greg Kroah-Hartman
parent 28a78e46f0
commit 7049825318
1 changed files with 19 additions and 14 deletions
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33
kernel/printk.c
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@ -235,7 +235,8 @@ static u32 log_next_idx;
static u64 clear_seq; static u64 clear_seq;
static u32 clear_idx; static u32 clear_idx;
#define LOG_LINE_MAX 1024 #define PREFIX_MAX 32
#define LOG_LINE_MAX 1024 - PREFIX_MAX
/* record buffer */ /* record buffer */
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
@ -876,7 +877,7 @@ static size_t msg_print_text(const struct log *msg, enum log_flags prev,
if (buf) { if (buf) {
if (print_prefix(msg, syslog, NULL) + if (print_prefix(msg, syslog, NULL) +
text_len + 1>= size - len) text_len + 1 >= size - len)
break; break;
if (prefix) if (prefix)
@ -907,7 +908,7 @@ static int syslog_print(char __user *buf, int size)
struct log *msg; struct log *msg;
int len = 0; int len = 0;
text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text) if (!text)
return -ENOMEM; return -ENOMEM;
@ -930,7 +931,8 @@ static int syslog_print(char __user *buf, int size)
skip = syslog_partial; skip = syslog_partial;
msg = log_from_idx(syslog_idx); msg = log_from_idx(syslog_idx);
n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX); n = msg_print_text(msg, syslog_prev, true, text,
LOG_LINE_MAX + PREFIX_MAX);
if (n - syslog_partial <= size) { if (n - syslog_partial <= size) {
/* message fits into buffer, move forward */ /* message fits into buffer, move forward */
syslog_idx = log_next(syslog_idx); syslog_idx = log_next(syslog_idx);
@ -969,7 +971,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
char *text; char *text;
int len = 0; int len = 0;
text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text) if (!text)
return -ENOMEM; return -ENOMEM;
@ -1022,7 +1024,8 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
struct log *msg = log_from_idx(idx); struct log *msg = log_from_idx(idx);
int textlen; int textlen;
textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX); textlen = msg_print_text(msg, prev, true, text,
LOG_LINE_MAX + PREFIX_MAX);
if (textlen < 0) { if (textlen < 0) {
len = textlen; len = textlen;
break; break;
@ -1367,15 +1370,15 @@ static struct cont {
bool flushed:1; /* buffer sealed and committed */ bool flushed:1; /* buffer sealed and committed */
} cont; } cont;
static void cont_flush(void) static void cont_flush(enum log_flags flags)
{ {
if (cont.flushed) if (cont.flushed)
return; return;
if (cont.len == 0) if (cont.len == 0)
return; return;
log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec, log_store(cont.facility, cont.level, LOG_NOCONS | flags,
NULL, 0, cont.buf, cont.len); cont.ts_nsec, NULL, 0, cont.buf, cont.len);
cont.flushed = true; cont.flushed = true;
} }
@ -1386,7 +1389,8 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
return false; return false;
if (cont.len + len > sizeof(cont.buf)) { if (cont.len + len > sizeof(cont.buf)) {
cont_flush(); /* the line gets too long, split it up in separate records */
cont_flush(LOG_CONT);
return false; return false;
} }
@ -1522,7 +1526,7 @@ asmlinkage int vprintk_emit(int facility, int level,
* or another task also prints continuation lines. * or another task also prints continuation lines.
*/ */
if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
cont_flush(); cont_flush(0);
/* buffer line if possible, otherwise store it right away */ /* buffer line if possible, otherwise store it right away */
if (!cont_add(facility, level, text, text_len)) if (!cont_add(facility, level, text, text_len))
@ -1540,7 +1544,7 @@ asmlinkage int vprintk_emit(int facility, int level,
if (cont.len && cont.owner == current) { if (cont.len && cont.owner == current) {
if (!(lflags & LOG_PREFIX)) if (!(lflags & LOG_PREFIX))
stored = cont_add(facility, level, text, text_len); stored = cont_add(facility, level, text, text_len);
cont_flush(); cont_flush(0);
} }
if (!stored) if (!stored)
@ -1633,7 +1637,8 @@ EXPORT_SYMBOL(printk);
#else #else
#define LOG_LINE_MAX 0 #define LOG_LINE_MAX 0
#define PREFIX_MAX 0
static struct cont { static struct cont {
size_t len; size_t len;
size_t cons; size_t cons;
@ -1938,7 +1943,7 @@ static enum log_flags console_prev;
*/ */
void console_unlock(void) void console_unlock(void)
{ {
static char text[LOG_LINE_MAX]; static char text[LOG_LINE_MAX + PREFIX_MAX];
static u64 seen_seq; static u64 seen_seq;
unsigned long flags; unsigned long flags;
bool wake_klogd = false; bool wake_klogd = false;