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ui-shared: prevent malicious filename from injecting headers
Jason A. Donenfeld Jason@zx2c4.com
Thu, 14 Jan 2016 14:28:37 +0100
commit

513b3863d999f91b47d7e9f26710390db55f9463

parent

4291453ec30656c2f59645d8a74cf295ce0253a9

3 files changed, 32 insertions(+), 3 deletions(-)

jump to
M html.chtml.c

@@ -239,6 +239,32 @@ if (t != txt)

html(txt); } +void html_header_arg_in_quotes(const char *txt) +{ + const char *t = txt; + while (t && *t) { + unsigned char c = *t; + const char *e = NULL; + if (c == '\\') + e = "\\\\"; + else if (c == '\r') + e = "\\r"; + else if (c == '\n') + e = "\\n"; + else if (c == '"') + e = "\\\""; + if (e) { + html_raw(txt, t - txt); + html(e); + txt = t + 1; + } + t++; + } + if (t != txt) + html(txt); + +} + void html_hidden(const char *name, const char *value) { html("<input type='hidden' name='");
M html.hhtml.h

@@ -23,6 +23,7 @@ extern void html_ntxt(int len, const char *txt);

extern void html_attr(const char *txt); extern void html_url_path(const char *txt); extern void html_url_arg(const char *txt); +extern void html_header_arg_in_quotes(const char *txt); extern void html_hidden(const char *name, const char *value); extern void html_option(const char *value, const char *text, const char *selected_value); extern void html_intoption(int value, const char *text, int selected_value);
M ui-shared.cui-shared.c

@@ -692,9 +692,11 @@ else if (ctx.page.mimetype)

htmlf("Content-Type: %s\n", ctx.page.mimetype); if (ctx.page.size) htmlf("Content-Length: %zd\n", ctx.page.size); - if (ctx.page.filename) - htmlf("Content-Disposition: inline; filename=\"%s\"\n", - ctx.page.filename); + if (ctx.page.filename) { + html("Content-Disposition: inline; filename=\""); + html_header_arg_in_quotes(ctx.page.filename); + html("\"\n"); + } if (!ctx.env.authenticated) html("Cache-Control: no-cache, no-store\n"); htmlf("Last-Modified: %s\n", http_date(ctx.page.modified));