From 95032b58a1ad0fde57518f17805ca721bb4563ad Mon Sep 17 00:00:00 2001 From: Shawn Bayern Date: Fri, 3 May 2024 00:46:18 -0700 Subject: [PATCH] Tighten boundary check in split(1) to prevent a potential buffer overflow. Before increasing sufflen, make sure the current name plus two (including the terminating NUL character and the to-be-added character) does not exceed the fixed buffer length, and stop immediately if this would occur. In worst case scenario the code would write an nul character beyond the boundary, however it would be caught by open(2) and based on the memory layout, we do not believe this would constitute a security vulnerability. MFC after: 3 days --- usr.bin/split/split.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/usr.bin/split/split.c b/usr.bin/split/split.c index 0241637c93a..2724f8a20cd 100644 --- a/usr.bin/split/split.c +++ b/usr.bin/split/split.c @@ -390,6 +390,10 @@ newfile(void) */ if (!dflag && autosfx && (fpnt[0] == 'y') && strspn(fpnt+1, "z") == strlen(fpnt+1)) { + /* Ensure the generated filenames will fit into the buffer. */ + if (strlen(fname) + 2 >= sizeof(fname)) + errx(EX_USAGE, "combined filenames would be too long"); + fpnt = fname + strlen(fname) - sufflen; fpnt[sufflen + 2] = '\0'; fpnt[0] = end;