jfs: fix slab-out-of-bounds read in ea_get()

Summary

In the Linux kernel, the following vulnerability has been resolved: jfs: fix slab-out-of-bounds read in ea_get() During the "size_check" label in ea_get(), the code checks if the extended attribute list (xattr) size matches ea_size. If not, it logs "ea_get: invalid extended attribute" and calls print_hex_dump(). Here, EALIST_SIZE(ea_buf->xattr) returns 4110417968, which exceeds INT_MAX (2,147,483,647). Then ea_size is clamped: int size = clamp_t(int, ea_size, 0, EALIST_SIZE(ea_buf->xattr)); Although clamp_t aims to bound ea_size between 0 and 4110417968, the upper limit is treated as an int, causing an overflow above 2^31 - 1. This leads "size" to wrap around and become negative (-184549328). The "size" is then passed to print_hex_dump() (called "len" in print_hex_dump()), it is passed as type size_t (an unsigned type), this is then stored inside a variable called "int remaining", which is then assigned to "int linelen" which is then passed to hex_dump_to_buffer(). In print_hex_dump() the for loop, iterates through 0 to len-1, where len is 18446744073525002176, calling hex_dump_to_buffer() on each iteration: for (i = 0; i < len; i += rowsize) { linelen = min(remaining, rowsize); remaining -= rowsize; hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, linebuf, sizeof(linebuf), ascii); ... } The expected stopping condition (i < len) is effectively broken since len is corrupted and very large. This eventually leads to the "ptr+i" being passed to hex_dump_to_buffer() to get closer to the end of the actual bounds of "ptr", eventually an out of bounds access is done in hex_dump_to_buffer() in the following for loop: for (j = 0; j < len; j++) { if (linebuflen < lx + 2) goto overflow2; ch = ptr[j]; ... } To fix this we should validate "EALIST_SIZE(ea_buf->xattr)" before it is utilised.

Timeline

1. Apr 18, 2025, 7:01 AM UTCCVE published
2. Oct 1, 2025, 4:13 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Aug 5, 2026, 12:04 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 5.4.287 · fixed in 5.4.292; From 5.10.231 · fixed in 5.10.236; From 5.15.174 · fixed in 5.15.180; From 6.1.120 · fixed in 6.1.134; From 6.6.64 · fixed in 6.6.87; From 6.12.2 · fixed in 6.12.23; From 4.19.325 · fixed in 4.20; From 6.11.11 · fixed in 6.12

• Linux Linux

  6.13

References 9