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Fri, 09 Jan 2026 12:05:26 -0800 (PST) Received: from [127.0.0.1] ([172.184.211.145]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2b1707da231sm12895565eec.34.2026.01.09.12.05.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Jan 2026 12:05:25 -0800 (PST) Message-Id: <7fe463d68aa58fd563053ee1cb87b2a8c1152957.1767989109.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "Karsten Blees via GitGitGadget" Date: Fri, 09 Jan 2026 20:05:07 +0000 Subject: [PATCH v2 3/5] strbuf_readlink(): avoid calling `readlink()` twice in corner-cases Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To: git@vger.kernel.org Cc: Patrick Steinhardt , Johannes Schindelin , Karsten Blees From: Karsten Blees The `strbuf_readlink()` function calls `readlink()`` twice if the hint argument specifies the exact size of the link target (e.g. by passing stat.st_size as returned by `lstat()`). This is necessary because `readlink(..., hint) == hint` could mean that the buffer was too small. Use `hint + 1` as buffer size to prevent this. Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- strbuf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/strbuf.c b/strbuf.c index 6c3851a7f8..44a8f6a554 100644 --- a/strbuf.c +++ b/strbuf.c @@ -578,12 +578,12 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint) while (hint < STRBUF_MAXLINK) { ssize_t len; - strbuf_grow(sb, hint); - len = readlink(path, sb->buf, hint); + strbuf_grow(sb, hint + 1); + len = readlink(path, sb->buf, hint + 1); if (len < 0) { if (errno != ERANGE) break; - } else if (len < hint) { + } else if (len <= hint) { strbuf_setlen(sb, len); return 0; } -- gitgitgadget