In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
smb\/client: validate new EOF for insert range<\/p>\n
smb3_insert_range() does not check if the new file size
\n(i_size + len) is valid. This allows FALLOC_FL_INSERT_RANGE to bypass
\nRLIMIT_FSIZE, exceed s_maxbytes, or produce a size outside the loff_t
\nrange.<\/p>\n
Use check_add_overflow() to calculate the new EOF. Validate it with
\ninode_newsize_ok() before modifying the file.<\/p>\n
Reproducer, using a file on a CIFS mount:<\/p>\n
\tbash -c ‘
\n\t\tFILE=\/mnt\/cifs\/repro<\/p>\n
\t\ttrap “” SIGXFSZ
\n\t\tulimit -f 3072\t\t# RLIMIT_FSIZE = 3 MiB<\/p>\n
\t\t# A regular write is stopped at 3 MiB.
\n\t\tdd if=\/dev\/zero of=”$FILE” bs=1M count=4 status=none
\n\t\tstat -c “size after write: %s” “$FILE”<\/p>\n
\t\t# Insert 2 MiB into a 2 MiB file.
\n\t\ttruncate -s 2M “$FILE”
\n\t\tfallocate -i -o 0 -l 2M “$FILE”
\n\t\tstat -c “size after insert: %s” “$FILE”
\n\t‘<\/p>\n
Before this change, the regular write stops at the 3 MiB limit, but
\ninsert range grows the file to 4 MiB:<\/p>\n
\tdd: error writing ‘\/mnt\/cifs\/repro’: File too large
\n\tsize after write: 3145728
\n\tsize after insert: 4194304<\/p>\n
After this change, insert range also fails at the limit and leaves the
\n2 MiB file unchanged:<\/p>\n
\tdd: error writing ‘\/mnt\/cifs\/repro’: File too large
\n\tsize after write: 3145728
\n\tfallocate: fallocate failed: File too large
\n\tsize after insert: 2097152<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
smb\/client: validate new EOF for insert range<\/p>\n
smb3_insert_range() does not check if the new file size
\n(i_size + len) is valid. Thi<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29281","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29281","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=29281"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29281"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}