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author | Jan Beulich <JBeulich@suse.com> | 2014-08-08 14:20:09 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-08 15:57:19 -0700 |
commit | 6e85bab6bc1019f9b87c53b32da3ad7791e7ddf9 (patch) | |
tree | 7f83156bdd6fa857286d224a3443dc5f481cbd74 /drivers | |
parent | 3710f597aca5af4f605cda9793a8b2f0a42bc29a (diff) | |
download | linux-6e85bab6bc1019f9b87c53b32da3ad7791e7ddf9.tar.gz linux-6e85bab6bc1019f9b87c53b32da3ad7791e7ddf9.tar.bz2 linux-6e85bab6bc1019f9b87c53b32da3ad7791e7ddf9.zip |
drivers/rtc/rtc-efi.c: check for invalid data coming back from UEFI
In particular seeing zero in eft->month is problematic, as it results in
-1 (converted to unsigned int, i.e. yielding 0xffffffff) getting passed
to rtc_year_days(), where the value gets used as an array index
(normally resulting in a crash). This was observed with the driver
enabled on x86 on some Fujitsu system (with possibly not up to date
firmware, but anyway).
Perhaps efi_read_alarm() should not fail if neither enabled nor pending
are set, but the returned time is invalid?
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reported-by: Raymund Will <rw@suse.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jingoo Han <jg1.han@samsung.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/rtc/rtc-efi.c | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c index c4c38431012e..8225b89de810 100644 --- a/drivers/rtc/rtc-efi.c +++ b/drivers/rtc/rtc-efi.c @@ -17,6 +17,7 @@ #include <linux/kernel.h> #include <linux/module.h> +#include <linux/stringify.h> #include <linux/time.h> #include <linux/platform_device.h> #include <linux/rtc.h> @@ -48,8 +49,8 @@ compute_wday(efi_time_t *eft) int y; int ndays = 0; - if (eft->year < 1998) { - pr_err("EFI year < 1998, invalid date\n"); + if (eft->year < EFI_RTC_EPOCH) { + pr_err("EFI year < " __stringify(EFI_RTC_EPOCH) ", invalid date\n"); return -1; } @@ -78,19 +79,36 @@ convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft) eft->timezone = EFI_UNSPECIFIED_TIMEZONE; } -static void +static bool convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime) { memset(wtime, 0, sizeof(*wtime)); + + if (eft->second >= 60) + return false; wtime->tm_sec = eft->second; + + if (eft->minute >= 60) + return false; wtime->tm_min = eft->minute; + + if (eft->hour >= 24) + return false; wtime->tm_hour = eft->hour; + + if (!eft->day || eft->day > 31) + return false; wtime->tm_mday = eft->day; + + if (!eft->month || eft->month > 12) + return false; wtime->tm_mon = eft->month - 1; wtime->tm_year = eft->year - 1900; /* day of the week [0-6], Sunday=0 */ wtime->tm_wday = compute_wday(eft); + if (wtime->tm_wday < 0) + return false; /* day in the year [1-365]*/ wtime->tm_yday = compute_yday(eft); @@ -106,6 +124,8 @@ convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime) default: wtime->tm_isdst = -1; } + + return true; } static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) @@ -122,7 +142,8 @@ static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) if (status != EFI_SUCCESS) return -EINVAL; - convert_from_efi_time(&eft, &wkalrm->time); + if (!convert_from_efi_time(&eft, &wkalrm->time)) + return -EIO; return rtc_valid_tm(&wkalrm->time); } @@ -163,7 +184,8 @@ static int efi_read_time(struct device *dev, struct rtc_time *tm) return -EINVAL; } - convert_from_efi_time(&eft, tm); + if (!convert_from_efi_time(&eft, tm)) + return -EIO; return rtc_valid_tm(tm); } |