6f747825fa
Fix one-byte overflow in SSH banner processing Resolves: rhbz#2138345 Fix double free() in error path Resolves: rhbz#2138347
58 lines
1.6 KiB
Diff
58 lines
1.6 KiB
Diff
diff --git a/ssh-keyscan.c b/ssh-keyscan.c
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index d29a03b4..d7283136 100644
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--- a/ssh-keyscan.c
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+++ b/ssh-keyscan.c
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@@ -490,6 +490,15 @@ congreet(int s)
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return;
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}
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+ /*
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+ * Read the server banner as per RFC4253 section 4.2. The "SSH-"
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+ * protocol identification string may be preceeded by an arbitarily
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+ * large banner which we must read and ignore. Loop while reading
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+ * newline-terminated lines until we have one starting with "SSH-".
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+ * The ID string cannot be longer than 255 characters although the
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+ * preceeding banner lines may (in which case they'll be discarded
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+ * in multiple iterations of the outer loop).
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+ */
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for (;;) {
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memset(buf, '\0', sizeof(buf));
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bufsiz = sizeof(buf);
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@@ -517,6 +526,11 @@ congreet(int s)
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conrecycle(s);
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return;
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}
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+ if (cp >= buf + sizeof(buf)) {
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+ error("%s: greeting exceeds allowable length", c->c_name);
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+ confree(s);
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+ return;
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+ }
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if (*cp != '\n' && *cp != '\r') {
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error("%s: bad greeting", c->c_name);
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confree(s);
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diff --git a/sshsig.c b/sshsig.c
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index 1e3b6398..eb2a931e 100644
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--- a/sshsig.c
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+++ b/sshsig.c
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@@ -491,7 +491,7 @@ hash_file(int fd, const char *hashalg, struct sshbuf **bp)
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{
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char *hex, rbuf[8192], hash[SSH_DIGEST_MAX_LENGTH];
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ssize_t n, total = 0;
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- struct ssh_digest_ctx *ctx;
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+ struct ssh_digest_ctx *ctx = NULL;
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int alg, oerrno, r = SSH_ERR_INTERNAL_ERROR;
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struct sshbuf *b = NULL;
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@@ -549,9 +548,11 @@ hash_file(int fd, const char *hashalg, struct sshbuf **bp)
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/* success */
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r = 0;
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out:
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+ oerrno = errno;
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sshbuf_free(b);
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ssh_digest_free(ctx);
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explicit_bzero(hash, sizeof(hash));
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+ errno = oerrno;
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return r;
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}
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