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| author | Arnd Bergmann <arnd@arndb.de> | 2019-11-05 09:39:51 +0100 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2019-12-18 18:07:31 +0100 |
| commit | 853bc0ab341b0c99619f83f4060dedcccad77b2a (patch) | |
| tree | ce5ecd2529f48e2b4544b88bf06bc09debd0c4db /arch/um/drivers/cow_user.c | |
| parent | 37e86e0fd0403f51d6dd49abd1469361714f6ca4 (diff) | |
| download | linux-853bc0ab341b0c99619f83f4060dedcccad77b2a.tar.gz linux-853bc0ab341b0c99619f83f4060dedcccad77b2a.tar.bz2 linux-853bc0ab341b0c99619f83f4060dedcccad77b2a.zip | |
um: ubd: use 64-bit time_t where possible
The ubd code suffers from a possible y2038 overflow on 32-bit
architectures, both for the cow header and the os_file_modtime()
function.
Replace time_t with time64_t to extend the ubd_kern side as much
as possible.
Whether this makes a difference for the user side depends on
the host libc implementation that may use either 32-bit or 64-bit
time_t.
For the cow file format, the header contains an unsigned 32-bit
timestamp, which is good until y2106, passing this through a
'long long' gives us a consistent interpretation between 32-bit
and 64-bit um kernels.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/um/drivers/cow_user.c')
| -rw-r--r-- | arch/um/drivers/cow_user.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c index 74b0c2686c95..29b46581ddd1 100644 --- a/arch/um/drivers/cow_user.c +++ b/arch/um/drivers/cow_user.c @@ -17,6 +17,7 @@ #define PATH_LEN_V1 256 +/* unsigned time_t works until year 2106 */ typedef __u32 time32_t; struct cow_header_v1 { @@ -197,7 +198,7 @@ int write_cow_header(char *cow_file, int fd, char *backing_file, int sectorsize, int alignment, unsigned long long *size) { struct cow_header_v3 *header; - unsigned long modtime; + long long modtime; int err; err = cow_seek_file(fd, 0); @@ -276,7 +277,7 @@ int file_reader(__u64 offset, char *buf, int len, void *arg) int read_cow_header(int (*reader)(__u64, char *, int, void *), void *arg, __u32 *version_out, char **backing_file_out, - time_t *mtime_out, unsigned long long *size_out, + long long *mtime_out, unsigned long long *size_out, int *sectorsize_out, __u32 *align_out, int *bitmap_offset_out) { @@ -363,7 +364,7 @@ int read_cow_header(int (*reader)(__u64, char *, int, void *), void *arg, /* * this was used until Dec2005 - 64bits are needed to represent - * 2038+. I.e. we can safely do this truncating cast. + * 2106+. I.e. we can safely do this truncating cast. * * Additionally, we must use be32toh() instead of be64toh(), since * the program used to use the former (tested - I got mtime |