xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

um: ubd: use 64-bit time_t where possible

Browse Source 
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>
This commit is contained in:
Arnd Bergmann
2019-11-05 09:39:51 +01:00
parent 37e86e0fd0
commit 853bc0ab34
5 changed files with 12 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
arch/um/drivers/cow_user.c
View File

@@ -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