In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
powerpc\/kexec_file: Prevent kexec range truncation<\/p>\n
Sashiko AI review pointed out the following issue.<\/p>\n
The __merge_memory_ranges() function incorrectly handles overlapping
\nmemory ranges when merging them. Although sort_memory_ranges() sorts all
\nranges by their start address in ascending order beforehand, the merge
\nlogic remains defective in two ways:<\/p>\n
1. It compares the current range’s start against the previous element (i-1)
\n instead of the running target index (idx)<\/p>\n
2. It unconditionally overwrites ‘ranges[idx].end’ with ‘ranges[i].end’.<\/p>\n
This logic flaw leads to critical memory truncation when a larger memory
\nrange completely subsumes subsequent smaller ranges.<\/p>\n
For example, consider a sorted input array with three ranges:
\n Range A (idx=0): [0x1000 – 0x9000]
\n Range B (i=1): [0x2000 – 0x5000] (completely inside Range A)
\n Range C (i=2): [0x6000 – 0x8000] (completely inside Range A)<\/p>\n
1. When i=1 (Range B):
\n ranges[1].start (0x2000) <= ranges[0].end + 1 (0x9001) is TRUE.
\n The code executes: ranges[0].end = ranges[1].end, which erroneously
\n shrinks Range A's end from 0x9000 down to 0x5000.<\/p>\n
2. When i=2 (Range C):
\n ranges[2].start (0x6000) <= ranges[1].end + 1 (0x5001) is FALSE.
\n The code falls into the else block, creating a broken new range.<\/p>\n
As a result, valid memory fragments [0x5001 – 0x5fff] and [0x8001 – 0x9000]
\nare completely lost from the kexec exclude lists, potentially allowing
\nthe crash kernel to overwrite active memory, causing data corruption
\nor crashes.<\/p>\n
Fix this by ensuring the start of the current range is compared against the
\nend of the active merged range (idx), and use max() to safely prevent the
\nouter boundary from being truncated.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
powerpc\/kexec_file: Prevent kexec range truncation<\/p>\n
Sashiko AI review pointed out the following issue.<\/p>\n
The __merge_memory_ranges()<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24649","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24649","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=24649"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24649"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24649"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}