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/openbmc/linux/drivers/mtd/ |
H A D | mtdchar.c | 6c6bc9ea Fri Jul 06 22:37:22 CDT 2018 Jann Horn <jannh@google.com> mtdchar: fix overflows in adjustment of `count`
The first checks in mtdchar_read() and mtdchar_write() attempt to limit `count` such that `*ppos + count <= mtd->size`. However, they ignore the possibility of `*ppos > mtd->size`, allowing the calculation of `count` to wrap around. `mtdchar_lseek()` prevents seeking beyond mtd->size, but the pread/pwrite syscalls bypass this.
I haven't found any codepath on which this actually causes dangerous behavior, but it seems like a sensible change anyway.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com> 6c6bc9ea Fri Jul 06 22:37:22 CDT 2018 Jann Horn <jannh@google.com> mtdchar: fix overflows in adjustment of `count` The first checks in mtdchar_read() and mtdchar_write() attempt to limit `count` such that `*ppos + count <= mtd->size`. However, they ignore the possibility of `*ppos > mtd->size`, allowing the calculation of `count` to wrap around. `mtdchar_lseek()` prevents seeking beyond mtd->size, but the pread/pwrite syscalls bypass this. I haven't found any codepath on which this actually causes dangerous behavior, but it seems like a sensible change anyway. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
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