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    SubjectRe: [PATCH] modpost: fix buffer overflow
    On Wed, 15 Mar 2006 15:57:28 +0100, Bernd Petrovitsch wrote:
    > Silly me. To make it more obvious whatz I really meant was:
    > ---- snip ----
    > if (buf->size - buf->pos < len + 1) {
    > while (buf->size - buf->pos < len + 1)
    > buf->size += 128;
    > buf->p = realloc(buf->p, buf->size);
    > }
    > ---- snip ----

    Yes, this is probably better. New version of the patch follows.

    ---->8----

    I got SIGABRT in modpost when compiling a module really deeply nested in
    a filesystem (path > 100 chars):

    > Building modules, stage 2.
    > MODPOST
    > *** glibc detected *** scripts/mod/modpost: realloc(): invalid next size: 0x0809f588 ***
    > [...]

    This patch fixes that problem.

    Signed-off-by: Jiri Benc <jbenc@suse.cz>

    --- linux-2.6.16-rc6.orig/scripts/mod/modpost.c
    +++ linux-2.6.16-rc6/scripts/mod/modpost.c
    @@ -553,7 +553,8 @@ void __attribute__((format(printf, 2, 3)
    va_start(ap, fmt);
    len = vsnprintf(tmp, SZ, fmt, ap);
    if (buf->size - buf->pos < len + 1) {
    - buf->size += 128;
    + while (buf->size - buf->pos < len + 1)
    + buf->size += 128;
    buf->p = realloc(buf->p, buf->size);
    }
    strncpy(buf->p + buf->pos, tmp, len + 1);

    --
    Jiri Benc
    SUSE Labs
    -
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