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CVE PROGRAM SOURCE RECORDUnscored

CVE-2024-42102

Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again" Patch series "mm: Avoid possible overflows in dirty throttling". Dirty throttling logic assumes dirty limits in page units fit into 32-bits. This patch series makes sure this is true (see patch 2/2 for more details). This patch (of 2): This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78. The commit is broken in several ways. Firstly, the removed (u64) cast from the multiplication will introduce a multiplication overflow on 32-bit archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the default settings with 4GB of RAM will trigger this). Secondly, the div64_u64() is unnecessarily expensive on 32-bit archs. We have div64_ul() in case we want to be safe & cheap. Thirdly, if dirty thresholds are larger than 1<<32 pages, then dirty balancing is going to blow up in many other spectacular ways anyway so trying to fix one possible overflow is just moot.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • c593d26fb5d577ef31b6e49a31e08ae3ebc1bc1e to < 253f9ea7e8e53a5176bd80ceb174907b10724c1aaffected
  • 1f12e4b3284d6c863f272eb2de0d4248ed211cf4 to < 23a28f5f3f6ca1e4184bd0e9631cd0944cf1c807affected
  • 81e7d2530d458548b90a5c5e76b77ad5e5d1c0df to < 145faa3d03688cbb7bbaaecbd84c01539852942caffected
  • 5099871b370335809c0fd1abad74d9c7c205d43f to < 2820005edae13b140f2d54267d1bd6bb23915f59affected
  • 16b1025eaa8fc223ab4273ece20d1c3a4211a95d to < cbbe17a324437c0ff99881a3ee453da45b228a00affected
  • ec18ec230301583395576915d274b407743d8f6c to < f6620df12cb6bdcad671d269debbb23573502f9daffected
  • 9319b647902cbd5cc884ac08a8a6d54ce111fc78 to < 000099d71648504fb9c7a4616f92c2b70c3e44ecaffected
  • 9319b647902cbd5cc884ac08a8a6d54ce111fc78 to < 30139c702048f1097342a31302cbd3d478f50c63affected
  • 65977bed167a92e87085e757fffa5798f7314c9faffected
  • 4.19.307 to < 4.19.318affected
  • 5.4.269 to < 5.4.280affected
  • 5.10.210 to < 5.10.222affected
  • 5.15.149 to < 5.15.163affected
  • 6.1.79 to < 6.1.98affected
  • 6.6.18 to < 6.6.39affected
  • 6.7.6 to < 6.8affected

Linux Linux

Default version status: affected

  • 6.8affected
  • 0 to < 6.8unaffected
  • 4.19.318 to ≤ 4.19.*unaffected
  • 5.4.280 to ≤ 5.4.*unaffected
  • 5.10.222 to ≤ 5.10.*unaffected
  • 5.15.163 to ≤ 5.15.*unaffected
  • 6.1.98 to ≤ 6.1.*unaffected
  • 6.6.39 to ≤ 6.6.*unaffected
  • 6.9.9 to ≤ 6.9.*unaffected
  • 6.10 to ≤ *unaffected

References