rss email digests over ssh because you're a cool kid
herald.dunkirk.sh
go
rss
rss-reader
ssh
charm
feat: add HTML sanitization for inline feed content
Implements safe HTML rendering for inline feeds by:
- Adding bluemonday library for HTML sanitization
- Creating sanitizeHTML function using UGCPolicy (allows safe tags, strips styles and unsafe elements)
- Introducing templateFeedItem and templateFeedGroup structs with SanitizedContent field
- Pre-sanitizing all feed content before template rendering
- Updating digest.html template to use SanitizedContent instead of raw Content
This prevents XSS attacks while still allowing safe HTML formatting like headings, links, lists, and basic text formatting in feed content.
+82
-4
+72
-3
email/render.go
+72
-3
email/render.go
···
6
6
htmltemplate "html/template"
7
7
texttemplate "text/template"
8
8
"time"
9
+
10
+
"github.com/microcosm-cc/bluemonday"
9
11
)
10
12
11
13
//go:embed templates/*
···
30
32
Published time.Time
31
33
}
32
34
35
+
// templateFeedItem is used for template rendering with sanitized HTML content
36
+
type templateFeedItem struct {
37
+
Title string
38
+
Link string
39
+
Content string // Original content for text template
40
+
SanitizedContent htmltemplate.HTML // Sanitized HTML for HTML template
41
+
Published time.Time
42
+
}
43
+
44
+
// templateFeedGroup is used for template rendering with sanitized items
45
+
type templateFeedGroup struct {
46
+
FeedName string
47
+
FeedURL string
48
+
Items []templateFeedItem
49
+
}
50
+
51
+
// sanitizeHTML sanitizes HTML content, allowing safe tags while stripping styles and unsafe elements
52
+
func sanitizeHTML(html string) string {
53
+
return policy.Sanitize(html)
54
+
}
55
+
33
56
var (
34
57
htmlTmpl *htmltemplate.Template
35
58
textTmpl *texttemplate.Template
59
+
policy *bluemonday.Policy
36
60
)
37
61
38
62
func init() {
···
45
69
if err != nil {
46
70
panic("failed to parse text template: " + err.Error())
47
71
}
72
+
73
+
// Initialize HTML sanitization policy
74
+
// UGCPolicy allows safe HTML tags but strips styles and unsafe elements
75
+
// This prevents XSS attacks while allowing basic formatting
76
+
policy = bluemonday.UGCPolicy()
48
77
}
49
78
50
79
func RenderDigest(data *DigestData, inline bool, daysUntilExpiry int, showUrgentBanner, showWarningBanner bool) (html string, text string, err error) {
51
-
tmplData := struct {
80
+
// Convert FeedGroups to templateFeedGroups with sanitized HTML content
81
+
sanitizedGroups := make([]templateFeedGroup, len(data.FeedGroups))
82
+
for i, group := range data.FeedGroups {
83
+
sanitizedItems := make([]templateFeedItem, len(group.Items))
84
+
for j, item := range group.Items {
85
+
sanitizedItems[j] = templateFeedItem{
86
+
Title: item.Title,
87
+
Link: item.Link,
88
+
Content: item.Content,
89
+
SanitizedContent: htmltemplate.HTML(sanitizeHTML(item.Content)),
90
+
Published: item.Published,
91
+
}
92
+
}
93
+
sanitizedGroups[i] = templateFeedGroup{
94
+
FeedName: group.FeedName,
95
+
FeedURL: group.FeedURL,
96
+
Items: sanitizedItems,
97
+
}
98
+
}
99
+
100
+
// Prepare template data for HTML template (with sanitized content)
101
+
htmlTmplData := struct {
102
+
ConfigName string
103
+
TotalItems int
104
+
FeedGroups []templateFeedGroup
105
+
Inline bool
106
+
DaysUntilExpiry int
107
+
ShowUrgentBanner bool
108
+
ShowWarningBanner bool
109
+
}{
110
+
ConfigName: data.ConfigName,
111
+
TotalItems: data.TotalItems,
112
+
FeedGroups: sanitizedGroups,
113
+
Inline: inline,
114
+
DaysUntilExpiry: daysUntilExpiry,
115
+
ShowUrgentBanner: showUrgentBanner,
116
+
ShowWarningBanner: showWarningBanner,
117
+
}
118
+
119
+
// Prepare template data for text template (with original content)
120
+
textTmplData := struct {
52
121
*DigestData
53
122
Inline bool
54
123
DaysUntilExpiry int
···
64
133
65
134
var htmlBuf, textBuf bytes.Buffer
66
135
67
-
if err = htmlTmpl.Execute(&htmlBuf, tmplData); err != nil {
136
+
if err = htmlTmpl.Execute(&htmlBuf, htmlTmplData); err != nil {
68
137
return "", "", err
69
138
}
70
139
71
-
if err = textTmpl.Execute(&textBuf, tmplData); err != nil {
140
+
if err = textTmpl.Execute(&textBuf, textTmplData); err != nil {
72
141
return "", "", err
73
142
}
74
143
+1
-1
email/templates/digest.html
+1
-1
email/templates/digest.html
+3
go.mod
+3
go.mod
···
27
27
github.com/andybalholm/cascadia v1.3.3 // indirect
28
28
github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be // indirect
29
29
github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
30
+
github.com/aymerick/douceur v0.2.0 // indirect
30
31
github.com/charmbracelet/bubbletea v1.3.10 // indirect
31
32
github.com/charmbracelet/colorprofile v0.4.1 // indirect
32
33
github.com/charmbracelet/keygen v0.5.4 // indirect
···
44
45
github.com/creack/pty v1.1.24 // indirect
45
46
github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
46
47
github.com/go-logfmt/logfmt v0.6.1 // indirect
48
+
github.com/gorilla/css v1.0.1 // indirect
47
49
github.com/inconshreveable/mousetrap v1.1.0 // indirect
48
50
github.com/json-iterator/go v1.1.12 // indirect
49
51
github.com/kr/fs v0.1.0 // indirect
···
51
53
github.com/mattn/go-isatty v0.0.20 // indirect
52
54
github.com/mattn/go-localereader v0.0.1 // indirect
53
55
github.com/mattn/go-runewidth v0.0.19 // indirect
56
+
github.com/microcosm-cc/bluemonday v1.0.27 // indirect
54
57
github.com/mmcdole/goxpp v1.1.1 // indirect
55
58
github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
56
59
github.com/modern-go/reflect2 v1.0.2 // indirect
+6
go.sum
+6
go.sum
···
12
12
github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
13
13
github.com/aymanbagabas/go-udiff v0.3.1 h1:LV+qyBQ2pqe0u42ZsUEtPiCaUoqgA9gYRDs3vj1nolY=
14
14
github.com/aymanbagabas/go-udiff v0.3.1/go.mod h1:G0fsKmG+P6ylD0r6N/KgQD/nWzgfnl8ZBcNLgcbrw8E=
15
+
github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
16
+
github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
15
17
github.com/charmbracelet/bubbletea v1.3.10 h1:otUDHWMMzQSB0Pkc87rm691KZ3SWa4KUlvF9nRvCICw=
16
18
github.com/charmbracelet/bubbletea v1.3.10/go.mod h1:ORQfo0fk8U+po9VaNvnV95UPWA1BitP1E0N6xJPlHr4=
17
19
github.com/charmbracelet/colorprofile v0.4.1 h1:a1lO03qTrSIRaK8c3JRxJDZOvhvIeSco3ej+ngLk1kk=
···
68
70
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
69
71
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
70
72
github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
73
+
github.com/gorilla/css v1.0.1 h1:ntNaBIghp6JmvWnxbZKANoLyuXTPZ4cAMlo6RyhlbO8=
74
+
github.com/gorilla/css v1.0.1/go.mod h1:BvnYkspnSzMmwRK+b8/xgNPLiIuNZr6vbZBTPQ2A3b0=
71
75
github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
72
76
github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
73
77
github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
···
88
92
github.com/mattn/go-runewidth v0.0.19/go.mod h1:XBkDxAl56ILZc9knddidhrOlY5R/pDhgLpndooCuJAs=
89
93
github.com/mattn/go-sqlite3 v1.14.33 h1:A5blZ5ulQo2AtayQ9/limgHEkFreKj1Dv226a1K73s0=
90
94
github.com/mattn/go-sqlite3 v1.14.33/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
95
+
github.com/microcosm-cc/bluemonday v1.0.27 h1:MpEUotklkwCSLeH+Qdx1VJgNqLlpY2KXwXFM08ygZfk=
96
+
github.com/microcosm-cc/bluemonday v1.0.27/go.mod h1:jFi9vgW+H7c3V0lb6nR74Ib/DIB5OBs92Dimizgw2cA=
91
97
github.com/mmcdole/gofeed v1.3.0 h1:5yn+HeqlcvjMeAI4gu6T+crm7d0anY85+M+v6fIFNG4=
92
98
github.com/mmcdole/gofeed v1.3.0/go.mod h1:9TGv2LcJhdXePDzxiuMnukhV2/zb6VtnZt1mS+SjkLE=
93
99
github.com/mmcdole/goxpp v1.1.1 h1:RGIX+D6iQRIunGHrKqnA2+700XMCnNv0bAOOv5MUhx8=