Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: minix: avoid overflow in bitmap block count calculation minix_check_superblock() uses minix_blocks_needed() to verify that the on-disk imap and zmap block counts are large enough for the advertised inode and zone counts. The helper currently performs DIV_ROUND_UP() in unsigned int arithmetic. A Minix v3 image can set s_ninodes or s_zones near UINT_MAX so the addition inside DIV_ROUND_UP() wraps to zero. That makes a zero imap/zmap block count look valid, after which minix_fill_super() can dereference s_imap[0] or s_zmap[0] even though no bitmap buffers were allocated. Impact: mounting a crafted Minix v3 image whose s_ninodes or s_zones is near UINT_MAX makes minix_check_superblock() accept a zero bitmap-block count and minix_fill_super() dereference s_imap[0]/s_zmap[0], panicking the kernel. The divisor is the bitmap capacity in bits, blocksize * 8, which is always a power of two: minix_fill_super() obtains the block size through sb_set_blocksize(), and blk_validate_block_size() rejects any size that is not a power of two. Use DIV_ROUND_UP_POW2(), which divides before adding the round-up term and so cannot overflow for a power-of-two divisor.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 2bb588cede1c1969e49c0a2822c8cb8b346b7682 before a11ebaab50d27d6c4c78506f84ff36452e0b901d; affected f57ccd4657c7f082dc47e5b9e18a883bb5f9118f before 959c95340a9e19cd333b4c18935fdeecbb2f319d; affected 31fefc18096cdc5549cfa54964d90e0b3229aedc before abe3536a4bedcc43de80b6d4d7e3d57e9ba382a5; affected 8c97a6ddc95690a938ded44b4e3202f03f15078c before 8a29e60e2176b02e04f8737c8b32b696230eb0c5; affected 8c97a6ddc95690a938ded44b4e3202f03f15078c before fb3e566cafc38fe3ba35e6843a2d529a3748870c; affected a051ecf5c5b0387840dc210413ed3bc7fbdaa69c; affected d791c544efd6b9c944b43cf7f502e5bcb02fb941; affected 66c7c239c65341f99ae388d4d53dc9df2bcb9925; affected 1efc128ee4adbc23e082715425ff895449d233bc; affected 6.6.128 before 6.6.145; affected 6.12.75 before 6.12.97; affected 6.18.16 before 6.18.40; affected 5.10.252 before 5.11; affected 5.15.202 before 5.16; affected 6.1.165 before 6.2; affected 6.19.6 before 6.20 |
| Linux / Linux | affected 7.0; unaffected 0 before 7.0; unaffected 6.6.145 through 6.6.*; unaffected 6.12.97 through 6.12.*; unaffected 6.18.40 through 6.18.*; unaffected 7.1.5 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/a11ebaab50d27d6c4c78506f84ff36452e0b901d
- https://git.kernel.org/stable/c/959c95340a9e19cd333b4c18935fdeecbb2f319d
- https://git.kernel.org/stable/c/abe3536a4bedcc43de80b6d4d7e3d57e9ba382a5
- https://git.kernel.org/stable/c/8a29e60e2176b02e04f8737c8b32b696230eb0c5
- https://git.kernel.org/stable/c/fb3e566cafc38fe3ba35e6843a2d529a3748870c