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| author | Ben Hutchings <ben@decadent.org.uk> | 2014-08-26 00:34:44 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-23 22:55:15 -0700 |
| commit | 655e5b7c031e84cf8c07cfd6a5944ce53cba1add (patch) | |
| tree | d99c06b802df92b1618fe67fe3a6a5e811b7b43b /drivers/base | |
| parent | 833c95456a70826d1384883b73fd23aff24d366f (diff) | |
| download | linux-655e5b7c031e84cf8c07cfd6a5944ce53cba1add.tar.bz2 | |
drivers/base: Fix length checks in create_syslog_header()/dev_vprintk_emit()
snprintf() returns the number of bytes that could have been written
(excluding the null), not the actual number of bytes written. Given a
long enough subsystem or device name, these functions will advance
beyond the end of the on-stack buffer in dev_vprintk_exit(), resulting
in an information leak or stack corruption. I don't know whether such
a long name is currently possible.
In case snprintf() returns a value >= the buffer size, do not add
structured logging information. Also WARN if this happens, so we can
fix the driver or increase the buffer size.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/core.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 20da3ad1696b..28b808c73e8e 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2007,6 +2007,8 @@ create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) return 0; pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys); + if (pos >= hdrlen) + goto overflow; /* * Add device identifier DEVICE=: @@ -2038,7 +2040,14 @@ create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) "DEVICE=+%s:%s", subsys, dev_name(dev)); } + if (pos >= hdrlen) + goto overflow; + return pos; + +overflow: + dev_WARN(dev, "device/subsystem name too long"); + return 0; } int dev_vprintk_emit(int level, const struct device *dev, |