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>
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@ -17,6 +17,7 @@
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#include <linux/kernel.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/module.h>
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#include <linux/stringify.h>
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#include <linux/time.h>
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#include <linux/time.h>
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#include <linux/platform_device.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#include <linux/rtc.h>
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@ -48,8 +49,8 @@ compute_wday(efi_time_t *eft)
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int y;
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int y;
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int ndays = 0;
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int ndays = 0;
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if (eft->year < 1998) {
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if (eft->year < EFI_RTC_EPOCH) {
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pr_err("EFI year < 1998, invalid date\n");
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pr_err("EFI year < " __stringify(EFI_RTC_EPOCH) ", invalid date\n");
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return -1;
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return -1;
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}
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}
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@ -78,19 +79,36 @@ convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
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eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
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eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
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}
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}
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static void
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static bool
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convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
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convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
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{
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{
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memset(wtime, 0, sizeof(*wtime));
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memset(wtime, 0, sizeof(*wtime));
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if (eft->second >= 60)
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return false;
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wtime->tm_sec = eft->second;
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wtime->tm_sec = eft->second;
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if (eft->minute >= 60)
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return false;
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wtime->tm_min = eft->minute;
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wtime->tm_min = eft->minute;
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if (eft->hour >= 24)
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return false;
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wtime->tm_hour = eft->hour;
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wtime->tm_hour = eft->hour;
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if (!eft->day || eft->day > 31)
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return false;
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wtime->tm_mday = eft->day;
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wtime->tm_mday = eft->day;
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if (!eft->month || eft->month > 12)
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return false;
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wtime->tm_mon = eft->month - 1;
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wtime->tm_mon = eft->month - 1;
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wtime->tm_year = eft->year - 1900;
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wtime->tm_year = eft->year - 1900;
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/* day of the week [0-6], Sunday=0 */
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/* day of the week [0-6], Sunday=0 */
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wtime->tm_wday = compute_wday(eft);
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wtime->tm_wday = compute_wday(eft);
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if (wtime->tm_wday < 0)
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return false;
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/* day in the year [1-365]*/
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/* day in the year [1-365]*/
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wtime->tm_yday = compute_yday(eft);
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wtime->tm_yday = compute_yday(eft);
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@ -106,6 +124,8 @@ convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
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default:
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default:
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wtime->tm_isdst = -1;
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wtime->tm_isdst = -1;
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}
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}
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return true;
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}
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}
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static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
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static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
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@ -122,7 +142,8 @@ static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
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if (status != EFI_SUCCESS)
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if (status != EFI_SUCCESS)
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return -EINVAL;
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return -EINVAL;
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convert_from_efi_time(&eft, &wkalrm->time);
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if (!convert_from_efi_time(&eft, &wkalrm->time))
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return -EIO;
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return rtc_valid_tm(&wkalrm->time);
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return rtc_valid_tm(&wkalrm->time);
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}
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}
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@ -163,7 +184,8 @@ static int efi_read_time(struct device *dev, struct rtc_time *tm)
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return -EINVAL;
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return -EINVAL;
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}
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}
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convert_from_efi_time(&eft, tm);
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if (!convert_from_efi_time(&eft, tm))
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return -EIO;
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return rtc_valid_tm(tm);
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return rtc_valid_tm(tm);
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}
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}
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