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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-07 21:00:52 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-07 21:00:52 -0700 |
commit | cef5d0f952a03d42051141742632078d488b0c6b (patch) | |
tree | 29b27c96f9f297b2cf84612a0dbb8dcc11ffa4d6 /kernel/printk | |
parent | 0fb02e718f5fd88b175387bc2a9313b27609f0da (diff) | |
parent | 077a1cc06f72f95efd077d433993c16191008e47 (diff) | |
download | linux-stable-cef5d0f952a03d42051141742632078d488b0c6b.tar.gz linux-stable-cef5d0f952a03d42051141742632078d488b0c6b.tar.bz2 linux-stable-cef5d0f952a03d42051141742632078d488b0c6b.zip |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Do not allow use of freed init data and code even when boot consoles
are forced to stay. Also check for the init memory more precisely.
- Some code clean up by starting contributors.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: Clean up do_syslog() error handling
printk/console: Enhance the check for consoles using init memory
printk/console: Always disable boot consoles that use init memory before it is freed
printk: Modify operators of printed_len and text_len
Diffstat (limited to 'kernel/printk')
-rw-r--r-- | kernel/printk/printk.c | 69 |
1 files changed, 32 insertions, 37 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 97bda7b0655b..512f7c2baedd 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1434,7 +1434,7 @@ int do_syslog(int type, char __user *buf, int len, int source) error = check_syslog_permissions(type, source); if (error) - goto out; + return error; switch (type) { case SYSLOG_ACTION_CLOSE: /* Close log */ @@ -1442,20 +1442,16 @@ int do_syslog(int type, char __user *buf, int len, int source) case SYSLOG_ACTION_OPEN: /* Open log */ break; case SYSLOG_ACTION_READ: /* Read from log */ - error = -EINVAL; if (!buf || len < 0) - goto out; - error = 0; + return -EINVAL; if (!len) - goto out; - if (!access_ok(VERIFY_WRITE, buf, len)) { - error = -EFAULT; - goto out; - } + return 0; + if (!access_ok(VERIFY_WRITE, buf, len)) + return -EFAULT; error = wait_event_interruptible(log_wait, syslog_seq != log_next_seq); if (error) - goto out; + return error; error = syslog_print(buf, len); break; /* Read/clear last kernel messages */ @@ -1464,16 +1460,12 @@ int do_syslog(int type, char __user *buf, int len, int source) /* FALL THRU */ /* Read last kernel messages */ case SYSLOG_ACTION_READ_ALL: - error = -EINVAL; if (!buf || len < 0) - goto out; - error = 0; + return -EINVAL; if (!len) - goto out; - if (!access_ok(VERIFY_WRITE, buf, len)) { - error = -EFAULT; - goto out; - } + return 0; + if (!access_ok(VERIFY_WRITE, buf, len)) + return -EFAULT; error = syslog_print_all(buf, len, clear); break; /* Clear ring buffer */ @@ -1495,15 +1487,13 @@ int do_syslog(int type, char __user *buf, int len, int source) break; /* Set level of messages printed to console */ case SYSLOG_ACTION_CONSOLE_LEVEL: - error = -EINVAL; if (len < 1 || len > 8) - goto out; + return -EINVAL; if (len < minimum_console_loglevel) len = minimum_console_loglevel; console_loglevel = len; /* Implicitly re-enable logging to console */ saved_console_loglevel = LOGLEVEL_DEFAULT; - error = 0; break; /* Number of chars in the log buffer */ case SYSLOG_ACTION_SIZE_UNREAD: @@ -1525,7 +1515,6 @@ int do_syslog(int type, char __user *buf, int len, int source) u64 seq = syslog_seq; u32 idx = syslog_idx; - error = 0; while (seq < log_next_seq) { struct printk_log *msg = log_from_idx(idx); @@ -1545,7 +1534,7 @@ int do_syslog(int type, char __user *buf, int len, int source) error = -EINVAL; break; } -out: + return error; } @@ -1697,10 +1686,10 @@ asmlinkage int vprintk_emit(int facility, int level, { static char textbuf[LOG_LINE_MAX]; char *text = textbuf; - size_t text_len = 0; + size_t text_len; enum log_flags lflags = 0; unsigned long flags; - int printed_len = 0; + int printed_len; bool in_sched = false; if (level == LOGLEVEL_SCHED) { @@ -1753,7 +1742,7 @@ asmlinkage int vprintk_emit(int facility, int level, if (dict) lflags |= LOG_PREFIX|LOG_NEWLINE; - printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len); + printed_len = log_output(facility, level, lflags, dict, dictlen, text, text_len); logbuf_unlock_irqrestore(flags); @@ -2649,9 +2638,8 @@ void __init console_init(void) * makes it difficult to diagnose problems that occur during this time. * * To mitigate this problem somewhat, only unregister consoles whose memory - * intersects with the init section. Note that code exists elsewhere to get - * rid of the boot console as soon as the proper console shows up, so there - * won't be side-effects from postponing the removal. + * intersects with the init section. Note that all other boot consoles will + * get unregistred when the real preferred console is registered. */ static int __init printk_late_init(void) { @@ -2659,16 +2647,23 @@ static int __init printk_late_init(void) int ret; for_each_console(con) { - if (!keep_bootcon && con->flags & CON_BOOT) { + if (!(con->flags & CON_BOOT)) + continue; + + /* Check addresses that might be used for enabled consoles. */ + if (init_section_intersects(con, sizeof(*con)) || + init_section_contains(con->write, 0) || + init_section_contains(con->read, 0) || + init_section_contains(con->device, 0) || + init_section_contains(con->unblank, 0) || + init_section_contains(con->data, 0)) { /* - * Make sure to unregister boot consoles whose data - * resides in the init section before the init section - * is discarded. Boot consoles whose data will stick - * around will automatically be unregistered when the - * proper console replaces them. + * Please, consider moving the reported consoles out + * of the init section. */ - if (init_section_intersects(con, sizeof(*con))) - unregister_console(con); + pr_warn("bootconsole [%s%d] uses init memory and must be disabled even before the real one is ready\n", + con->name, con->index); + unregister_console(con); } } ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, |