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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2024-26885

bpf: Fix DEVMAP_HASH overflow check on 32-bit arches

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix DEVMAP_HASH overflow check on 32-bit arches The devmap code allocates a number hash buckets equal to the next power of two of the max_entries value provided when creating the map. When rounding up to the next power of two, the 32-bit variable storing the number of buckets can overflow, and the code checks for overflow by checking if the truncated 32-bit value is equal to 0. However, on 32-bit arches the rounding up itself can overflow mid-way through, because it ends up doing a left-shift of 32 bits on an unsigned long value. If the size of an unsigned long is four bytes, this is undefined behaviour, so there is no guarantee that we'll end up with a nice and tidy 0-value at the end. Syzbot managed to turn this into a crash on arm32 by creating a DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it. Fix this by moving the overflow check to before the rounding up operation.

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

  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < 1f5e352b9088211fa5eb4e1639cd365f4f7d2f65affected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < 4b81a9f92b3676cb74b907a7a209b3d15bd9a7f9affected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < c826502bed93970f2fd488918a7b8d5f1d30e2e3affected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < edf7990baa48de5097daa9ac02e06cb4c798a737affected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < 250051acc21f9d4c5c595e4fcb55986ea08c4691affected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < 22079b3a423382335f47d9ed32114e6c9fe88d7caffected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < e89386f62ce9a9ab9a94835a9890883c23d9d52caffected
  • 6f9d451ab1a33728adb72d7ff66a7b374d665176 to < 281d464a34f540de166cee74b723e97ac2515ec3affected

Linux Linux

Default version status: affected

  • 5.4affected
  • 0 to < 5.4unaffected
  • 5.4.285 to ≤ 5.4.*unaffected
  • 5.10.227 to ≤ 5.10.*unaffected
  • 5.15.153 to ≤ 5.15.*unaffected
  • 6.1.83 to ≤ 6.1.*unaffected
  • 6.6.23 to ≤ 6.6.*unaffected
  • 6.7.11 to ≤ 6.7.*unaffected
  • 6.8.2 to ≤ 6.8.*unaffected
  • 6.9 to ≤ *unaffected

References