# [PATCH] Fix memory leak in function handle_content_type 8 messages from 2025-06-13 to 2025-06-16. Participants: Alex via GitGitGadget, Kristoffer Haugsbakk, Jinyao Guo, Junio C Hamano, Lidong Yan. Thread: https://gitlist.dev/t/63641 ## Alex via GitGitGadget, 2025-06-13 16:52 Subject: [PATCH] Fix memory leak in function handle_content_type Message-ID: URL: https://gitlist.dev/e/pull.1997.git.git.1749833577767.gitgitgadget%40gmail.com ``` From: jinyaoguo The function handle_content_type allocates memory for boundary using xmalloc(sizeof(struct strbuf)). If (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) is true, the function returns without freeing boundary. Signed-off-by: Alex Guo --- Fix memory leak in function handle_content_type The function handle_content_type allocates memory for boundary using xmalloc(sizeof(struct strbuf)). If (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) is true, the function returns without freeing boundary. Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1997%2Fmugitya03%2Fmlk-2-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1997/mugitya03/mlk-2-v1 Pull-Request: https://github.com/git/git/pull/1997 mailinfo.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mailinfo.c b/mailinfo.c index ee4597da6be..e0ea358311f 100644 --- a/mailinfo.c +++ b/mailinfo.c @@ -266,6 +266,9 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) error("Too many boundaries to handle"); mi->input_error = -1; mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; + strbuf_release(boundary); + free(boundary); + boundary = NULL; return; } *(mi->content_top) = boundary; base-commit: 9edff09aec9b5aaa3d5528129bb279a4d34cf5b3 -- gitgitgadget ``` ## Kristoffer Haugsbakk, 2025-06-13 16:59 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: <44066126-ece9-4c77-b38a-292b6f748955@app.fastmail.com> URL: https://gitlist.dev/e/44066126-ece9-4c77-b38a-292b6f748955%40app.fastmail.com In-Reply-To: ``` On Fri, Jun 13, 2025, at 18:52, Alex via GitGitGadget wrote: > From: jinyaoguo > > [snip] > > Signed-off-by: Alex Guo Like what was said on another patch[1] the From and Signed-off-by names need to match. I didn’t see a resolution to that? If forwarding you need to add your signoff after theirs. [1]: https://lore.kernel.org/git/xmqq1psfxgyv.fsf@gitster.g/ -- Kristoffer Haugsbakk ``` ## Jinyao Guo, 2025-06-13 18:36 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: URL: https://gitlist.dev/e/SA1PR22MB3999874B7FD9FFF7D90C9F89E477A%40SA1PR22MB3999.namprd22.prod.outlook.com In-Reply-To: <44066126-ece9-4c77-b38a-292b6f748955@app.fastmail.com> ``` Hi Kristoffer, Sorry for that. I’m still getting familiar with the Git patch submission workflow and missed the sign-off requirement. I believe the confusion came from using two different Git identities. I’ve now added individual “Signed-off-by” lines for both accounts. From b39b1a8176a344a2fa2c46a6d0ffc27a7bfd9edd Mon Sep 17 00:00:00 2001 From: jinyaoguo Date: Thu, 12 Jun 2025 18:48:24 -0400 Subject: [PATCH] Fix memory leak in function handle_content_type The function handle_content_type allocates memory for boundary using xmalloc(sizeof(struct strbuf)). If (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) is true, the function returns without freeing boundary. Signed-off-by: Alex Guo Signed-off-by: jinyaoguo --- mailinfo.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mailinfo.c b/mailinfo.c index ee4597da6b..e0ea358311 100644 --- a/mailinfo.c +++ b/mailinfo.c @@ -266,6 +266,9 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) error("Too many boundaries to handle"); mi->input_error = -1; mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; + strbuf_release(boundary); + free(boundary); + boundary = NULL; return; } *(mi->content_top) = boundary; -- 2.34.1 ________________________________________ From: Kristoffer Haugsbakk Sent: Friday, June 13, 2025 12:59 To: Josh Soref ; git@vger.kernel.org Cc: Alex ; Jinyao Guo Subject: Re: [PATCH] Fix memory leak in function handle_content_type [You don't often get email from kristofferhaugsbakk@fastmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] ---- External Email: Use caution with attachments, links, or sharing data ---- On Fri, Jun 13, 2025, at 18:52, Alex via GitGitGadget wrote: > From: jinyaoguo > > [snip] > > Signed-off-by: Alex Guo Like what was said on another patch[1] the From and Signed-off-by names need to match. I didn’t see a resolution to that? If forwarding you need to add your signoff after theirs. [1]: https://lore.kernel.org/git/xmqq1psfxgyv.fsf@gitster.g/ -- Kristoffer Haugsbakk ``` ## Junio C Hamano, 2025-06-13 19:06 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: URL: https://gitlist.dev/e/xmqq7c1f8nr2.fsf%40gitster.g In-Reply-To: ``` Jinyao Guo writes: > ... I believe > the confusion came from using two different Git identities. I’ve > now added individual “Signed-off-by” lines for both accounts. Please do not do this, if these two are the same single person. Instead, pick the one you want to be known as to this community, and use that consistently while working on this project. Thanks. ``` ## Jinyao Guo, 2025-06-13 19:26 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: URL: https://gitlist.dev/e/SA1PR22MB399911638F342E1AA20F014AE477A%40SA1PR22MB3999.namprd22.prod.outlook.com In-Reply-To: ``` Sure. I'll choose one account and use it consistently. Here is the edited patch: From 04b286cb2e736c3a53287b6ddf406e704f19fb2e Mon Sep 17 00:00:00 2001 From: jinyaoguo Date: Thu, 12 Jun 2025 18:48:24 -0400 Subject: [PATCH] Fix memory leak in function handle_content_type The function handle_content_type allocates memory for boundary using xmalloc(sizeof(struct strbuf)). If (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) is true, the function returns without freeing boundary. Signed-off-by: jinyaoguo --- mailinfo.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mailinfo.c b/mailinfo.c index ee4597da6b..e0ea358311 100644 --- a/mailinfo.c +++ b/mailinfo.c @@ -266,6 +266,9 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) error("Too many boundaries to handle"); mi->input_error = -1; mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; + strbuf_release(boundary); + free(boundary); + boundary = NULL; return; } *(mi->content_top) = boundary; -- 2.34.1 Best, Jinyao ________________________________________ From: Junio C Hamano Sent: Friday, June 13, 2025 15:06 To: Jinyao Guo Cc: Kristoffer Haugsbakk ; Josh Soref ; git@vger.kernel.org ; Alex Subject: Re: [PATCH] Fix memory leak in function handle_content_type   ---- External Email: Use caution with attachments, links, or sharing data ---- Jinyao Guo writes: > ... I believe > the confusion came from using two different Git identities.  I’ve > now added individual “Signed-off-by” lines for both accounts. Please do not do this, if these two are the same single person. Instead, pick the one you want to be known as to this community, and use that consistently while working on this project. Thanks. ``` ## Junio C Hamano, 2025-06-14 16:45 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: URL: https://gitlist.dev/e/xmqq1prm6zlx.fsf%40gitster.g In-Reply-To: ``` Jinyao Guo writes: > @@ -266,6 +266,9 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) > error("Too many boundaries to handle"); > mi->input_error = -1; > mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; > + strbuf_release(boundary); > + free(boundary); > + boundary = NULL; > return; > } > *(mi->content_top) = boundary; "boundary" is a on-stack local variable. There is no need to assign NULL to it immediately before you return. In the post-context of this hunk, we free it but leave the variable pointing at a random place after that before returning. ``` ## Lidong Yan, 2025-06-15 12:55 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: <8C3C7F5F-9442-4C63-9280-D46A683C9F4D@gmail.com> URL: https://gitlist.dev/e/8C3C7F5F-9442-4C63-9280-D46A683C9F4D%40gmail.com In-Reply-To: ``` Jinyao Guo writes： > > Sure. I'll choose one account and use it consistently. > > Here is the edited patch: > > From 04b286cb2e736c3a53287b6ddf406e704f19fb2e Mon Sep 17 00:00:00 2001 > From: jinyaoguo > Date: Thu, 12 Jun 2025 18:48:24 -0400 > Subject: [PATCH] Fix memory leak in function handle_content_type > > The function handle_content_type allocates memory for boundary > using xmalloc(sizeof(struct strbuf)). If (++mi->content_top >= > &mi->content[MAX_BOUNDARIES]) is true, the function returns > without freeing boundary. > > Signed-off-by: jinyaoguo > --- > mailinfo.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mailinfo.c b/mailinfo.c > index ee4597da6b..e0ea358311 100644 > --- a/mailinfo.c > +++ b/mailinfo.c > @@ -266,6 +266,9 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) > error("Too many boundaries to handle"); > mi->input_error = -1; > mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; > + strbuf_release(boundary); > + free(boundary); > + boundary = NULL; > return; > } > *(mi->content_top) = boundary; > -- > 2.34.1 May be using goto here would be better. Like: --- diff --git a/mailinfo.c b/mailinfo.c index ee4597da6b..83358b7517 100644 --- a/mailinfo.c +++ b/mailinfo.c @@ -266,13 +266,14 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) error("Too many boundaries to handle"); mi->input_error = -1; mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; - return; + goto out; } *(mi->content_top) = boundary; boundary = NULL; } slurp_attr(line->buf, "charset=", &mi->charset); +out: if (boundary) { strbuf_release(boundary); free(boundary); — Lidong ``` ## Junio C Hamano, 2025-06-16 01:01 Subject: Re: [PATCH] Fix memory leak in function handle_content_type Message-ID: URL: https://gitlist.dev/e/xmqqldps4i00.fsf%40gitster.g In-Reply-To: <8C3C7F5F-9442-4C63-9280-D46A683C9F4D@gmail.com> ``` Lidong Yan writes: > Subject: Re: [PATCH] Fix memory leak in function handle_content_type The subject should probably be something like Subject: [PATCH] mailinfo.c: plug memory leak in handle_content_type() > May be using goto here would be better. Like: > > --- > diff --git a/mailinfo.c b/mailinfo.c > index ee4597da6b..83358b7517 100644 > --- a/mailinfo.c > +++ b/mailinfo.c > @@ -266,13 +266,14 @@ static void handle_content_type(struct mailinfo *mi, struct strbuf *line) > error("Too many boundaries to handle"); > mi->input_error = -1; > mi->content_top = &mi->content[MAX_BOUNDARIES] - 1; > - return; > + goto out; > } > *(mi->content_top) = boundary; > boundary = NULL; > } > slurp_attr(line->buf, "charset=", &mi->charset); > > +out: > if (boundary) { > strbuf_release(boundary); > free(boundary); > — Yup, that one looks good enough. If we wanted to clean up this code path even further, I think the first clean-up to do is to reconsider the use of "struct strbuf *" (instead of "const char *") in *(mi->content_top). strbuf is a fine and less error-prone mechanism to use while you have to manipulate character strings (like parsing from input line to formulate the boundary string), but once this function computed what was asked by the caller, the computed result (like the boundary string) almost always do not need to be editable. But such a code improvement is totally outside the topic of this patch. ```