From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>,
Laurent Vivier <lvivier@redhat.com>
Subject: [PATCH v2 1/5] util: Be more defensive about buffer overruns in read_file()
Date: Wed, 7 Jan 2026 11:16:05 +1100 [thread overview]
Message-ID: <20260107001609.910615-2-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20260107001609.910615-1-david@gibson.dropbear.id.au>
clang-21.1.7 complains about read_file(), thinking that total_read might
come to exceed buf_size, leading to an out of bounds access at the end of
the function. In fact, the semantics of read()'s return mean this can't
ever happen. But we already have to check for the total_read == buf_size
case, so it's basically free to change it to >= and suppress the error.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
---
util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/util.c b/util.c
index 27303950..a48f727c 100644
--- a/util.c
+++ b/util.c
@@ -715,7 +715,7 @@ static ssize_t read_file(const char *path, char *buf, size_t buf_size)
close(fd);
- if (total_read == buf_size) {
+ if (total_read >= buf_size) {
buf[buf_size - 1] = '\0';
return -ENOBUFS;
}
--
2.52.0
next prev parent reply other threads:[~2026-01-07 0:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-07 0:16 [PATCH v2 0/5] Fixes for Fedora 43 David Gibson
2026-01-07 0:16 ` David Gibson [this message]
2026-01-07 0:16 ` [PATCH v2 2/5] migrate: Don't use terminator element for versions[] array David Gibson
2026-01-07 0:16 ` [PATCH v2 3/5] treewide: Don't rely on terminator records in ip[46].dns arrays David Gibson
2026-01-07 0:16 ` [PATCH v2 4/5] test: Handle Operating System Command escapes in terminal output David Gibson
2026-01-07 0:16 ` [PATCH v2 5/5] test: Include sshd-auth in mbuto guest image David Gibson
2026-01-07 1:46 ` IGNORE, SORRY Re: [PATCH v2 0/5] Fixes for Fedora 43 David Gibson
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