From 179776f9e6c4bd2f423c78fcf8b1e4cb4afc4c45 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Wed, 28 Feb 2024 17:38:46 -0500 Subject: [PATCH] upload-pack: accept only a single packfile-uri line When we see a packfile-uri line from the client, we use string_list_split() to split it on commas and store the result in a string_list. A single packfile-uri line is therefore limited to storing ~64kb, the size of a pkt-line. But we'll happily accept multiple such lines, and each line appends to the string list, growing without bound. In theory this could be useful, making: 0017packfile-uris http 0018packfile-uris https equivalent to: 001dpackfile-uris http,https But the protocol documentation doesn't indicate that this should work (and indeed, refers to this in the singular as "the following argument can be included in the client's request"). And the client-side implementation in fetch-pack has always sent a single line (JGit appears to understand the line on the server side but has no client-side implementation, and libgit2 understands neither). If we were worried about compatibility, we could instead just put a limit on the maximum number of values we'd accept. The current client implementation limits itself to only two values: "http" and "https", so something like "256" would be more than enough. But accepting only a single line seems more in line with the protocol documentation, and matches other parts of the protocol (e.g., we will not accept a second "filter" line). We'll also make this more explicit in the protocol documentation; as above, I think this was always the intent, but there's no harm in making it clear. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- Documentation/gitprotocol-v2.txt | 3 ++- upload-pack.c | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/gitprotocol-v2.txt b/Documentation/gitprotocol-v2.txt index 837ea6171e..414bc625d5 100644 --- a/Documentation/gitprotocol-v2.txt +++ b/Documentation/gitprotocol-v2.txt @@ -362,7 +362,8 @@ included in the client's request: If the 'packfile-uris' feature is advertised, the following argument can be included in the client's request as well as the potential addition of the 'packfile-uris' section in the server's response as -explained below. +explained below. Note that at most one `packfile-uris` line can be sent +to the server. packfile-uris Indicates to the server that the client is willing to receive diff --git a/upload-pack.c b/upload-pack.c index 8b47576ec7..2a5c52666e 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -1646,6 +1646,9 @@ static void process_args(struct packet_reader *request, } if (skip_prefix(arg, "packfile-uris ", &p)) { + if (data->uri_protocols.nr) + send_err_and_die(data, + "multiple packfile-uris lines forbidden"); string_list_split(&data->uri_protocols, p, ',', -1); continue; } -- 2.11.4.GIT