Fix: Sector/Size overflow from uint32_t #5829
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This should resolve issue 3 in #5780 |
deepikabhavnani
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geky
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Jan 12, 2018
| @@ -196,20 +196,24 @@ DRESULT disk_read(BYTE pdrv, BYTE *buff, DWORD sector, UINT count) | |||
| { | |||
| debug_if(FFS_DBG, "disk_read(sector %d, count %d) on pdrv [%d]\n", sector, count, pdrv); | |||
| DWORD ssize = disk_get_sector_size(pdrv); | |||
| int err = _ffs[pdrv]->read(buff, sector*ssize, count*ssize); | |||
| bd_addr_t addr = (bd_addr_t)sector * ssize; | |||
| bd_size_t size = (bd_size_t)count*ssize; | |||
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nit: consistent style for these two lines.
| return err ? RES_PARERR : RES_OK; | ||
| } | ||
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| DRESULT disk_write(BYTE pdrv, const BYTE *buff, DWORD sector, UINT count) | ||
| { | ||
| debug_if(FFS_DBG, "disk_write(sector %d, count %d) on pdrv [%d]\n", sector, count, pdrv); | ||
| DWORD ssize = disk_get_sector_size(pdrv); | ||
| int err = _ffs[pdrv]->erase(sector*ssize, count*ssize); | ||
| bd_addr_t addr = (bd_addr_t)sector * ssize; | ||
| bd_size_t size = (bd_size_t)count*ssize; |
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nit: consistent style for these two lines
FATFilesystem declares sector count and size as uint32_t and block device class arguments are addr and size which is uint64_t While passing arguments to program/read/write API's of block device, multiplication of uint32_t*uint32_t was not typecasted properly to uint64_t which resulted in MSB truncation. Eg. If block 0x800000 is accessed with block size 0x200, addr to be passed (0x800000*0x200)0x100000000, but actual address passed was 0x0 which resulted in over-writting the root directory, and hence corrupted filesystem
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/morph build |
Build : SUCCESSBuild number : 859 Triggering tests/morph test |
Exporter Build : SUCCESSBuild number : 530 |
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/morph uvisor-test |
Test : SUCCESSBuild number : 703 |
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Travis restarted due to failing update command, once green, it shall be ready |
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FATFilesystem declares sector count and size as uint32_t and block device class arguments are addr and size which is uint64_t. While passing arguments to program/read/write API's of block device, multiplication of uint32_t*uint32_t was not type-casted to uint64_t which resulted in truncation.
Example of FAT corruption:
If sector 0x800000 is accessed with block size 0x200, addr to be passed 0x1 0000 0000 (0x800000*0x200), but actual address passed was 0x0000 0000 which resulted in over-writting the root directory, and hence corrupted filesystem.